The guy has no job and hasn't been making payments.

Or take the money and use it toward down payments on several properties? 

I would not have a problem covering the higher mortgage payment.

I will cancel before it's time for another payment.

The liquidity is determined by the offered yield, and strength of the paper in multiple metrics (Seasoning, down payment, borrower credit, equity, etc).

Unless you can provide your private lender with secured double digit returns, I agree with most, your dad may have to do this on his own, or simply have you intern with him on this deal. 

u can not require in most states for tenants to do maintenance only to keep neat and tidyI offer a base rent -0 per cent above market and an early "on or before rent due date received" payment discounted rentNot a late feeIf you do NOT enlist in a mortgage qualification coaching service and leave the tenant to procrastinate on get loan pre qualified, in 30 years of doing lease options I see the tenant not being successful at getting a home loan

I am currently trying to save for the down payment of my first property and wanted some advice about getting financing.

Leveraged-1/2 of the monthly rent = the maximum payment you should have on the property.  

Pre-approval for a Mortgage means you are approved for a total amount of added debt based on the monthly payments you will have to make to pay off that debt.