Can a verbal agreement between my elderly mother and I be enforced?

While in the process of caring for my elderly mother and after I sold her house in GA and moved her in to my home in TN, she and I came up with a plan to find a lot near my house and have a tiny house built using the money she had from the sale of her house in GA. I found a lot near by and we purchased it in her name with her money. We then discussed and agreed that her money and the lot should be put in my name to secure it from her mounting unpaid medical bills. Her money was then put in my bank account and the lot was to be transferred to my name with a quit claim deed. I would use the money to pay to have the house built. Her investment would be secured in the house in my name. At her death my husband and I would disburse and distribute her investment to her heirs. We would then take ownership of the house. The house is almost finished and mother is refusing to sign the quit claim deed because my sister has interfered. She wants the house. Can the agreement between us be enforced?