He donated land to build a mosque, then he wanted to build on top of it a meeting place for his extended family
Question

A man donated a piece of land to build a mosque, then later on it was suggested that he could add the construction of a meeting place for his extended family to the construction of the mosque. Is that permissible?
Praise be to Allah.I put this question to our shaykh, ‘Abd ar-Rahman al-Barrak (may Allah preserve him), and he replied:
So long as the donation of land has already been done, whether in word or in deed, such as starting to build the mosque, then the land is no longer his and he has no right to do anything with the land that is contrary to what he intended when he donated it. End quote.
See also the answers to questions no. 146753 and 144829 .
And Allah knows best.