Selling in negative equity

I am co-owner of a 3 bed semi with my brother valued at 190k and the mortgage owing is 205k. He has offered to buy the house for 190k, the max mortgage available on his wage including taking out a credit union loan to make up the difference, but only if I pay the 15k owing on the original mortgage.

He is currently living there and renting out one room, so I have to add every month to make my half of the payments.

Do I take the offer and get out of the mortgage for 15k or do I sit tight and hope he doesn't lose his job?

Interesting one. Does one deal with this as a business transaction or a family arrangement?

Wont advise on which is the better deal as one would have to speculate on the long term value of the property.
you have to view this along with your other personal considerations / commitments. If you are happy to rescind ownership of the property and escape a mortgage commitment at a cost of 15K, then theres your answer.
However if you view the property as a long term investment and are receiving rent and can sustain the payments, then you have another answer...

No right answer, just options which may be very different depending on personal circumstance / expectations.

Its all well and good mentioning this, but What's your own status?

If you were to seperate it out the below seems the most accurate option to me.

Your brother is buying the house for 190K
There is an outstanding amount of 15K

If your brother was any other buyer then yourself and your brother would be splitting the 15K so I would say you should just be paying 7.5K.

He took the risk of negative equity also.

Bearing in mind this is only correct if the property is valued at 190K.

Thanks for the comments. Firstly, to Balou my brother is stretched to the limit getting the 190k mortgage so can't afford to take the hit on the negative equity as well.

To watcher and pope john 11 my circumstance is that I am in a secure job and living with a partner who has a similar sized mortgage in a 2 bed terraced house. I would hope to start putting money away to buy a bigger house should we decide to have a family. I can afford to pay my half of the mortgage now, but my fear is that I may end up liable for the full mortgage or that when I want to get a bigger home the bank won't loan me any more money.