Sale of family cemetery plots

My family needs to sell a portion of the cemetery plots my parents bought about 40 years ago. My brothers and sisters need to pay for my mother's funeral plans with the proceeds of this sale. How will this sale affect my mother's medicare coverage? She does not have any income other that her monthly social security check.
We have tried to contact Medicare but have not been able to speak with anyone there; Medicare phones are automated.

Any informtion is welcomed.

Javier