Ohhh okay so basically my Jeremy is very much based off personal experience and he lives with his addict single mother and takes care of his younger siblings (I haven't decided how many). His living conditions aren't just poor, they are atrocious. Michael's home life isn't the best either, perhaps just as atrocious behind closed doors, but Jeremy has all his needs taken care of when he's over so he absolutely loves hanging out at his best friend's place. (They probably met in 1st grade and have been best friends since, especially because the other kids tend to think they're kind of weird/gross.)
And that's where Henry comes in. Michael much prefers being over at his place so naturally he takes his best friend with him as well! Now Henry does like playing weird and icky games with Michael sometimes but it's totally okay because he's nice and his family is fun!
Being the predatory piece of shit that Henry is, he does see the potential in Jeremy. But he's much more careful at first, just observing the relationship between Michael and him. It doesn't take him very long to realize though that not only is Jeremy a bit (a lot) slower than Michael mentally, but his "family" wouldn't even notice if the kid came home with a god damn missing limb.
Henry starts out slow, offering comfort and attention (!) to Jeremy but once he realizes how gullible the kid is he quickly gives in and starts regularly abusing him. Jeremy is far more clueless but also less sensitive than Michael so Henry really can keep going until he's worn out.
It's just a shame he isn't as elfin and sweet as Michael...