Does my husband not have the right to write a deed of ownership for the apartment in his name after he built it with his own money, or in my name, when my mother refuses this?

The mother's action of taking the husband's money to build an apartment in her name is wrong and an unlawful appropriation of funds. She must register the apartment in the name of the husband or the wife, and there is no harm in that, especially since the husband paid its price. It is possible to stipulate in the contract that the wife or husband does not own the land of the apartment to reassure the mother.