Well if a Muslim refuses to read anything on Answering Islam, then let me at least qoute the Islamic traditions on this particular matter:
Sahih Muslim
Book 008, Number 3424:
' A'isha (Allah be pleased with her) reported that Sahla bint Suhail came to Allah's Apostle (may peace be upon him) and said: Messenger of Allah, I see on the face of Abu Hudhaifa (signs of disgust) on entering of Salim (who is an ally) into (our house), whereupon Allah's Apostle (may peace be upon him) said: Suckle him. She said: How can I suckle him as he is a grown-up man? Allah's Messenger (may peace be upon him) smiled and said: I already know that he is a young man. 'Amr has made this addition in his narration that he participated in the Battle of Badr and in the narration of Ibn 'Umar (the words are): Allah's Messenger (may peace be upon him) laughed.
Book 008, Number 3425:
'A'isha (Allah be pleased with her) reported that Salim, the freed slave of Abu Hadhaifa, lived with him and his family in their house. She (i. e. the daughter of Suhail came to Allah's Apostle (may peace be upon him) and said: Salim has attained (puberty) as men attain, and he understands what they understand, and he enters our house freely, I, however, perceive that something (rankles) in the heart of Abu Hudhaifa, whereupon Allah's Apostle (may peace be upon him) said to her: Suckle him and you would become unlawful for him, and (the rankling) which Abu Hudhaifa feels in his heart will disappear. She returned and said: So I suckled him, and what (was there) in the heart of Abu Hudhaifa disappeared.
Book 008, Number 3427:
Umm Salama said to 'A'isha (Allah be pleased with her): A young boy who is at the threshold of puberty comes to you. I, however, do not like that he should come to me, whereupon 'A'isha (Allah be pleased with her) said: Don't you see in Allah's Messenger (may peace be upon him) a model for you? She also said: The wife of Abu Hudhaifa said: Messenger of Allah, Salim comes to me and now he is a (grown-up) person, and there is something that (rankles) in the mind of Abu Hudhaifa about him, whereupon Allah's Messenger (may peace be upon him) said: Suckle him (so that he may become your foster-child), and thus he may be able to come to you (freely).
Book 008, Number 3428:
Zainab daughter of Abu Salama reported: I heard Umm Salama, the wife of Allah's Apostle (may peace be upon himy, saying to 'A'isha: By Allah, I do not like to be seen by a young boy who has passed the period of fosterage, whereupon she ('A'isha) said: Why is it so? Sahla daughter of Suhail came to Allah's Messenger (may peace be upon him) and said: Allah's Messenger, I swear by Allah that I see in the face of Abu Hudhaifa (the signs of disgust) on account of entering of Salim (in the house), whereupon Allah's Messenger (may peace be upon him) said: Suckle him. She (Sahla bint Suhail) said: He has a beard. But he (again) said: Suckle him, and it would remove what is there (expression of disgust) on the face of Abu Hudhaifa. She said: (I did that) and, by Allah, I did not see (any sign of disgust) on the face of Abu Hadhaifa.
Imam Malik’s Muwatta
Book 30, Number 30.1.8:
Yahya related to me from Malik from Nafi that Safiyya bint Abi Ubayd told him that Hafsa, umm al-muminin, sent Asim ibn Abdullah ibn Sad to her sister Fatima bint Umar ibn al-Khattab for her to suckle him ten times so that he could come in to see her. She did it, so he used to come in to see her.
Book 30, Number 30.2.12:
Yahya related to me from Malik from Ibn Shihab that he was asked about the suckling of an older person. He said, ''Urwa ibn az-Zubayr informed me that Abu Hudhayfa ibn Utba ibn Rabia, one of the companions of the Messenger of Allah, may Allah bless him and grant him peace, who was present at Badr, adopted Salim (who is called Salim, the mawla of Abu Hudhayfa) as the Messenger of Allah, may Allah bless him and grant him peace, adopted Zayd ibn Haritha. He thought of him as his son, and Abu Hudhayfa married him to his brother's sister, Fatima bint al-Walid ibn Utba ibn Rabia, who was at that time among the first emigrants. She was one of the best unmarried women of the Quraysh. When Allah the Exalted sent down in His Book what He sent down about Zayd ibn Haritha, 'Call them after their true fathers. That is more equitable in the sight of Allah. If you do not know who their fathers were then they are your brothers in the deen and your mawali,' (Sura 33 ayat 5) people in this position were traced back to their fathers. When the father was not known, they were traced to their mawla.
"Sahla bint Suhayl who was the wife of Abu Hudhayfa, and one of the tribe of Amr ibn Luayy, came to the Messenger of Allah, may Allah bless him and grant him peace, and said, 'Messenger of Allah! We think of Salim as a son and he comes in to see me while I am uncovered. We only have one room, so what do you think about the situation?' The Messenger of Allah, may Allah bless him and grant him peace, said, 'Give him five drinks of your milk and he will be mahram by it.' She then saw him as a foster son. A'isha umm al-muminin took that as a precedent for whatever men she wanted to be able to come to see her. She ordered her sister, Umm Kulthum bint Abi Bakr as-Siddiq and the daughters of her brother to give milk to whichever men she wanted to be able to come in to see her. The rest of the wives of the Prophet, may Allah bless him and grant him peace, refused to let anyone come in to them by such nursing. They said, 'No! By Allah! We think that what the Messenger of Allah, may Allah bless him and grant him peace, ordered Sahla bint Suhayl to do was only an indulgence concerning the nursing of Salim alone. No! By Allah! No one will come in upon us by such nursing!'
"This is what the wives of the Prophet, may Allah bless him and grant him peace, thought about the suckling of an older person."
Book 30, Number 30.2.13:
Yahya related to me from Malik that Abdullah ibn Dinar said, "A man came to Abdullah ibn Umar when I was with him at the place where judgments were given and asked him about the suckling of an older person. Abdullah ibn Umar replied, ‘A man came to Umar ibn al-Khattab and said, 'I have a slave-girl and I used to have intercourse with her. My wife went to her and suckled her. When I went to the girl, my wife told me to watch out, because she had suckled her!' Umar told him TO BEAT HIS WIFE and to go to his slave-girl because kinship by suckling was only by the suckling of the young.’"
Book 30, Number 30.2.14:
Yahya related to me from Malik from Yahya ibn Said that a man said to Abu Musa al-Ashari, "I drank some milk from my wife's breasts and it went into my stomach." Abu Musa said, "I can only but think that she is haram for you." Abdullah ibn Masud said, "Look at what opinion you are giving the man." Abu Musa said, "Then what do you say?" Abdullah ibn Masud said, "There is only kinship by suckling in the first two years." Abu Musa said, "Do not ask me about anything while this learned man is among you."