Hi,
If your son is cognitively and physically (other than incontinence) normal, I would think that he should be able to change his own diaper if he only wets. If he has fecal incontinence it might be a bit more complicated. Whether or not he uses disposable diapers would also make a difference in how frequently he changes and how much assistance he may need.
After years of dealing with this I have found that the current higher end disposable diapers (Abena X-Plus...I think small would fit a 10 year-old) worn under plastic pants are enough to discretely deal with total bladder incontinence (i.e infrequent leaks, can be worn under normal clothing, change every three to four hours).
Good luck!
Mike