I'm using K9 .... it's free, easy, and almost 'too good' , but actually needed and protects the people AND the computer(from a lot of soulish and spiritual and electronic maliciousness .
I started using it way way way too late for my now 21 year old son.
Not that alone, but watch with strict rules what is on the computer --- be VERY strict. You won't be sorry later.
IF you're not very strict, you will be sorry later. Learned from experience. ('knew it' before, but didn't practice it long enough as my son got older.) . . .
Start with his understanding that EVERYTHING is subject to you. Everything in your control. Watch/check/double-check all the websites he visits and their content.
Of course, pray always, that will make the biggest difference always. That too I fell behind in, far short of even just what I knew.
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