Sell ​​an apartment with usufruct (my mother's pension) and invest it for you?

Hello dear financial people, I and my three siblings inherited ¼ of an apartment when my father died about 10 years ago. My mother has usufruct on the apartment and it is intended as her retirement provision. Either live cheaply, or rent out and use the income to supplement your pension. This is intended as a brainstorming session and not our set path. I'm just trying to find arguments/ways for and against? She would now like to move back to her homeland when she is older