Am I sinful for not carrying out my mother’s will that I not register properties in my wife’s name? And is my mother’s anger, apparent in a dream, related to that? What do you advise me?

It is permissible to gift the apartment to the wife, and the mother's will, which is based on a vision and therefore holds no weight, does not need to be executed. This will is not obligatory. Fulfilling the parents' covenant after their death is obligatory for matters that are obligatory, and it is recommendable for matters that are recommendable.