Student finance application/separated parents w/different incomes

From what I've read elsewhere and got told about in a 'read between lines' kind of way by someone at Student finance Wales a while ago, I want to have something clarified as our son doesn't want to get in any trouble. Although the person on the phone basically said he can choose whichever parent when I outlined the situation I seem to be worrying about it!

His Dad lives in one place and is on low income.
I live elsewhere, 6 miles away, closer to Uni, and am on a higher income.

It is my understanding that our son is allowed to apply with his Dad as the sponsor so he can get the full grant, even if our son lives with ME and just 'visits' his Dad. It's some weird loophole I guess? Weird, but perfectly allowable.

The app form was a bit confusing. I think he might have put down his Dad's address as 'home address', thinking that needed to match the address of whoever was sponsoring him. Then my address was used for post. Should he UPDATE the home address to be MY address? If so, how to do that? Or should he just forget about it and just make sure next year to get the finer details accurate?

Either way, when applying for next year, if he is still living with ME, can he put down his home address as MINE but still have his Dad on the application form as his sponsor?

Thanks.