Yes. Your mother is entitled to a share of the proceeds based on her age. The older she is, the smaller her share. This is because the value of her interest is based on her life expectancy, based on actuarial tables. With a smaller life expectancy, her value decreases.
Another issue you and your sister may want to consider is capital gains taxes on the sale of the property. If you sell it during your mother’s life, you and your sister will have to pay taxes on the capital gain attributed to your share of the proceeds. If, instead, you retain the property until your mother’s death, you’ll receive a step up in basis and likely avoid any capital gains.
Harry S. Margolis practices elder law, estate, and special needs planning in Boston and Wellesley, Massachusetts. He is the founder of ElderLawAnswers.com and answers consumer questions about estate planning issues here and at AskHarry.info.