Two Years of steady employment, preferably with same employer.
Last two years Income should be the same or increasing.
Credit report should typically have less than two thirty day lates in last two years with a minimum credit score of 620 or higher.
Bankruptcy must be at least two years old, with perfect credit since discharge.
Foreclosures must be at least three years old, with perfect credit since.
Gerard has it right - your friend's best bet is to improve their credit history. While you may find a program and lender willing to offer financing for any given credit score, your friend may be not qualify due to the items within the credit report that caused their score to be so low. Almost anybody can get financing with a large enough down payment and the willingness to pay high interest rates, but generally if your friend is having trouble maintaining a good credit score now then adding a mortgage to the mix will not improve anything.
Feel free to contact me if your friend would like me to suggest ways to improve their credit.