Following is another option that you might not have considered. (You probably should work with a knowledgeable real-estate attorney and title agent/attorney to help you set up the following transaction.)
You could work with an attorney to help you set up an entity (LLC, S-/C-Corp, etc), and to help you set up a land contract for that entity to acquire your brother's property. You could also work with a title company to set up an escrow/servicing account to hold the title and handle the payments. And you could also have that attorney to draft a lease agreement for the arrangement with your brother. Since the title, in a land contract transaction, doesn't transfer until the completion of the terms therein, this transaction should not trigger any "due on sale" clause in your brother's original agreement. (You'll of course want to verify this with your own attorney.)
After your brother gets out of his jam, then you can either cancel the contract or simply sell him the entity.
I like Daniels response regarding loaning your brother the money, but if he is in a situation where he's lost his job, had medical bills, etc. where he will still not be able to make the payment, a mortgage mod or forebearance would be better.
Any reputable agent who does these does not charge upfront fees, you should still consult with a reputable real estate attorney in the Broward area to see what they recommend and what they would charge for their services. It is fairly easy to do a mortgage mod or forebearance agreement if your brother has mitigating circumstances, especially if he has a Freddie Mac or Fannie Mae loan. To help stop the pain, if you are willing to loan him the money (bless your heart!) then find an attorney and see what the recommend after reviewing all of the information.
Good luck to you both
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.