Does the reward for reciting the Quran and giving charity reach a deceased mother if the donor intends that, and is the donor deprived of reward if he dedicates all his charities to his mother?

The reward for reading Quran and giving charity that a son dedicates to his mother reaches her. There is also a saying among some scholars that the son receives a reward similar to what he dedicated to his mother. Giving charity on behalf of oneself is not obligatory; rather, it is a voluntary act.