Yes it is God's will that none perish. However, God has created man with his own sovereign will, and He respects it.
I must admit surprise that anyone who believes in free will would articulate their position in terms of the "sovereignty of man." Yet, after thinking about it, I agree with the writer of the above post, that the sovereignty of man in salvation is exactly what the free will doctrine accomplishes. God then is no sovereign. He gave up his sovereignty. Then God cannot save anyone, but sits on the throne of his non-sovereignty creates a salvation power, and then watches and hopes that man, in mans sovereignty will make use of that power of salvation and save himself with the power of salvation created by God.
I am not asking if anyone believes in free will, or does not believe in free will. I am asking if you agree that the doctrine of mans free will makes man sovereign? I would define the term "free will" as that doctrine which affirms denies mans nature as so sinful that all mankind is in rebellion against God. The doctrine of "free will" then means that mans nature is morally neutral, so that man can make either the good choice in salvation, or the bad choice and reject Gods power for salvation that is provided.