My son filed his taxes but is claimed by his father... son took out loans for school and so did dad. Sons loans are larger then dads so who claimed the credit on their taxes?

A dependent cannot claim any education expenses or credits on their tax return.  Only the person claiming the dependent student on their tax return is eligible to claim the education expenses and credits.

But student loans can only be claimed by the person legally responsible for paying the loan and only what they actually paid (however a student can clam reguardless of who paid it, but not if a dependent).  If the fathers name is not on the loan, he cannot claim the interest paid and neither can the dependent.  This may be a case where nobody can claim it.