The ruling on giving a daughter

Q: I have a son who is 40 years old now and is of weak mental growth. His mental growth ratio is one year per seven years as stated by a doctor. He is very frivolous and often angry. He sometimes behaves like a seven or ten-year-old child and sometimes like a man of the same age. He has asked for years (Part No. 18; Page No. 192) to be married. Is it permissible for us to marry him, bearing in mind that there is a source of sustenance for him and his would-be wife? Will his utterance of divorce while angry be enforceable? The source of sustenance is that we will buy him a house to live in an apartment thereof and rent other apartments to sustain him and his wife, if Allah destines him to marry.

A: It is permissible for you to marry him out of his own money as it guarantees his chastity and guarding him against sources of corruption. Moreover, he and his would-be wife and children must be sustained from his money if he has any. If he has no money, his sustenance will be the responsibility of those on whom his sustenance is obligatory such as his father, mother or the like. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.