Your brother can quit claim the deed to you, but your lender will consider this a "sale" and therefore there will be closing costs associated with this transaction. You can't just 'take over the mortgage' unless it is assumable.
There are also many ways for your brother to get help with the situation that doesn't involve you, or it could involve your assistance. It depends on both of you, as well as what type of loan he has:
Is it a Freddie Mac, Fannie Mae, FHA Loan, VA, assumable, adjustable, fixed? Since the loan to value is so good, the mortgage comapny will be willing to help out if he wants to stay in the house. Who placed the $489K value on it?
The best thing to do at this point is to consult with an experienced agent on the matter or get a real estate attorney to help guide you.
If I can be of any further assistance, please let me know.