I'm working on a deal currently where my customer needs to refinance in order to keep his home and remove his ex-wife from the existing mortgage and title. My customer has excellent credit but doesn't make enough money for his debt-ratio to qualify for a loan in today's tight mortgage market. His Dad has offered to help him out so that his son can keep his home and his grandchildren can continue to live in the home that they are accustomed.
Luckily, FHA has a program that allows a non-occupying co-borrower. FHA only offers programs for primary residences (no investment properties or vacation homes) but will allow the Dad to go on the loan and use his income and assets to qualify, along with the son's, and not be required to live in the house. The co-borrower's income and assets and credit are used as qualifiers, as well as their debts. And, it's important to note that the co-borrower is just as responsible for the debt as the borrower, even though they're not living in the home.
This is a great program for situations such as this, as well as for First Time Homebuyers when the parents are willing to help their children purchase their first home.
Another great thing about FHA mortgages is that they allow for up to 97% of the purchase price/value to be borrowed, requiring a modest down payment.