I think it is best for you to qualify by yourself. Your Father's situation is unacceptable for mortgage financing.
I have found that CONSUMER ACTION is an excellent resource for objective advice on all things credit related. You'll find free and sincere advice on everything from settling collection accounts to rebuilding credit to building credit from scratch on their website http://www.consumer-action.org/.
Beware of anyone offering to "repair" credit! The Federal Trade Commission issued a stern warning last year that such offers are scams. Find more from the FTC HERE. http://www.ftc.gov/bcp/edu/microsites/moneymatters/dealing-wâ€¦