C.O.
You can actually call the IRS with these questions and they will answer them for you and tell you what forms you need, who you can claim - what you can and cannot claim...that will help you more than here - because it's coming straight from the horses mouth...
I do know that you are not allowed to claim car payments or interest on your taxes...it's MILEAGE - keep a log of the odometer reading and date of each dr trip...then if you ever get audited, you will have back up- not just a guesstimate of the mileage!!
If your father is not filing taxes - even on disability - I don't think he can claim mortgage points or the interest write off....so really - call the IRS...go to:
http://www.irs.gov - you will get phone numbers to call and the forms you need......and if things are that complicated - you might benefit by paying a tax accountant to do your taxes for you...then you are covered that way as well..
GOOD LUCK!!!