Claiming Interest As A Tenant With Consent Of Owner
I financed a house for my daughter and son-in-law. They have been making the payments. Is it possible for them to somehow claim the interest on the mortgage on their taxes with my cooperation? 
You should grant deed them the property and
have them keep their cancelled checks and
they should be fine! Check with your CPA
to make sure.
Jeffrey Adam
If you actually financed it thru some type of owner financing, like a land contract, that had principle and interest payments, then yes. You as the lender, must send them a 1098 form listing the total interest paid. As far as taxes goes, they should be able to just use their cancelled check as a receipt.
If they are just paying the payments on a loan in your name, you could probably just give them the 1098 interest statement that you received. You, of course, couldn't use it on your taxes, though. Before doing anything, I'd check with you tax advisor and get a professional opinion.
Roger