I understand. However, Ch 13 does not go by how much you owe; it goes by how much you make which will determine how much you can pay back. Do me a favor and read this article (all 5 pages):
http://www.bankrate.com/brm/green/debt-consolidation/basics5-1a.asp
(you may need to copy and paste the link into your browser)
This should help you determine which filing is best for you. Let me know what you think and if you have any more questions, feel free to ask away.
Also, you should try to get more information from an attorney who specializes in bankruptcy. There are also organizations who can help you if you cannot afford to pay. I do know that the court will allow you to file for free under extreme hardship. Get on this as soon as possible. The longer you wait, the worse this situation will get.
In the meantime, work on that relationship with your mother. Do not let this loan continue to cause a strain on your relationship. It simply is not worth it.