She has no other relatives and ls very demanding... she used to have help to cook and clean so although she ls in great health thinks it's beneath her. She ls low on funds or l would put her in lovely assisted living. But l am not left in the best money situation so can l claim her on taxes tho she's not related?
You have to calculate her "total support", including food, lodging, clothing, education, medical and dental care, recreation, transportation, and similar necessities. Figure out what the "fair market value" to rent her room is. How much of her money is spent to support her, and how much of your money - including the rent that you don't charge her - is spent to support her? I'm pretty sure you can't count the value of the care you provide for her, but if you pay a friend or child to granny-sit, you could count that.
http://www.irs.gov/pub/irs-pdf/p501.pdf Page 17 and after. If you have a specific question, "hug" me and I will try to answer.
You are to be blessed to be taking care of your MIL and don't let her "bully" you with her demands. You need to stay healthy in order to be of help to anyone.
Keep us posted. xxxooo
Yes, you should get professional help with this, but start by looking at the link to the IRS website.
If your income is very low, claiming her might not help you, if you don't pay a lot of taxes yourself.
though you probably already filed for 2012, if you did your own taxes and miss that point, you can always file an amended return.