Is it that he is using someone else's computer? I hate porn and would flip if someone was engaging in porn sites on my computer. There are tons of freeware out there but you need to find one that will screen what you choose and not block out regular stuff by mistake. (some net nannies would block TE because of the word estrogen in the title.)
I guess what I'm wondering is... if he is of age to drop out and get his GED, then he is an adult? In that case, I just don't feel like I'd have a right to say anything for an adult, in the privacy of where they live (their room), on their own computer, out of site of younger children, etc. Yeah, I know I'm opening myself up to all kinds of nasty backlash here... I'm someone's kid too. I know my Mom would have a fit even at my current age. But, she would also know that it's none of her business. (She'd still give me h*ll though. ) That's why I'm a good kid.