Social Security benefits are never taxable. They only get exposed to tax if the income from other sources reaches $16,000.00 if single. I am not sure how you arrived at the $20,000.00 AGI figure. Your mother can deduct all of the out of pocket medical expenses she incurred this year on her Schedule A. This would include Medicare payments as well. Hopefully, this will reduce her income to below the taxable level.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"