The 8832 applies to the parents only. Not to anyone else. If the child is claimed by anyone other that non-custodial parent that has the signed 8332 from the custodial parent, that is not proof of anything.
" I will be able to prove to the IRS that I pay over 1/2 of my youngest son's support, "
Why bother? If you are the non-custodial parent with a signed 8332 from the custodial parent, you don't have to prove anything to anyone. But if someone else claims the dependent that 8332 is for, it's possible you could be audited. But I doubt that would happen unless the custodial parent who signed that 8332 wants to make a stink about it with the IRS.
