I'm assuming this means a contract with no mortgage clause.
The problem is for the dad. He's paying for something he won't own and which you might change your mind on. Or might blame him if a) property prices collapse b) that he forced you into a bad purchase c) that the mortgage does not come thru ................. d) mortgage is higher than you expected
I'd want a contract from you stating you know what you are doing and wont blame him for your decisions.