Can I be forced to sell real estate in Chapter 13 Bankruptcy?

I just found out that I jointly own property with my brother that had been owned by my mother when she was alive. He took care of her finances when she was alive and he is now wanting to sell this piece of property. I do not want to sell the property, but he is threatening to disclose this to the bankruptcy trustee if I do not agree to his terms for the sale of the property which is less than half(my percent of ownership) of the amount of sale. I am trying to get in touch with my bankruptcy attorney to let him know what is going on. I didn't disclose this when filing bankruptcy because did not know my mother had put me on the deed years ago. I checked with real estate and they think it is probably worth only about $12,000 total and this needs to be split between three siblings. Is there some type of exemption on this amount of money or what happens when I disclose this to the trustee? If it is sold will the trustee keep the money and distribute it among creditors or do I get to keep this? If I'm able to pay for this without making a loan, can I buy my brother's part out under Chapter 13?