N.P.
Get wet wipes and a waste basket to put near the toilet. My daughter doesn't like wiping her butt with toilet paper because she says it rips off and gets stuck in her bum. So I bought wipes at Costco and taught her that they can NOT go in the toilet. They are big enough that she doesn't have to worry about it not covering her hand up when she wipes and the garbage can is RIGHT THERE so she just drops it in. Yea it's kinda gross having poo wipes in a can next to the toilet but it's better than a plumbing bill and now she takes care of her own butt. She's only five but the wipes worked for us.
And if he hates to wash his hair, good thing he's a boy. I'd get him a nice military buzz cut so he doesn't have to worry about it and neither do you.