Oh look, Pwnies!
Robert, as much as many of us would appreciate a pay, we would much rather walk your son through the exercises through the forum. It will also help him understand the material better.
We do this a lot in our homework section, and you can think of it as a sort of tutoring with no pay. We aren't here 24/7, so answers might take longer than with an "instant" tutor, but we do help out, specially when we see the student trying to solve things for themselves.
Try to be a bit more specific as to where your son struggles with the material, maybe? I know he has ADD and it makes it hard for him to concentrate, but the benefit of a forum is to walk him through it on his pace. He can also join us in the chatroom (click on 'chat' above), though, I must warn, the chatroom is often home to our "idle" members, is more for a 'fun' passing of time. We are there to help but not 24/7 so try not to get frustrated if you don't get immediate answers.
Posting through the forum will be much more helpful, and will also comply with our rules.
It will likely help your son much more than us solving the problems for him, specially with the lack of a tutor to walk him through the problems using his style of learning.
If he just wants to cram the subject, he can look things up online; out of experience (I am tutoring myself, and I have had a student with ADD) this type of cramming isn't enough. The student needs to first understand what he's doing, and then 'cram' as many problems as possible to 'bring it home'. Understanding the stuff is key, though, and that will be best achieved if he just sits down and sees where he gets stuck.
Who knows, he might even get a B ;)
~moo