When is it permissible to shave the beard during the year of mourning

A mourner for his father who usually shaves his beard (in a permissible manner), when can he resume shaving his beard?

It is permissible to shave the beard in a permissible manner immediately after the conclusion of the thirty days, even without reproach. Subsequently, according to the basic law, one may shave as usual, but one who is stringent will shave after reproach, or thirty days without reproach.

It is written in the responsa Noda B'Yehuda, first edition - Orach Chaim, Siman 14: "And although we are stringent with the measure of reproach, and the Rema wrote three months, it is known that this is for those who do not shave their beards, only their heads. But in countries where they shave their beards, after two or three weeks it becomes very unpleasant, and the short hairs growing on their beards appear as thorns in their eyes and in the eyes of all who see them, as seen in the days of mourning, where literally a day is considered a year." And so it is written in the responsa Chatam Sofer, part 2 (Yoreh De'ah), Siman 347: "I have already stated in some responses that the measure of reproach mentioned in the rulings is for those who do not shave except for their heads, and it suffices to shave every three months, but for Ashkenazim who are accustomed to shaving their beards, it is more repulsive and detestable after thirty days, and the measure of reproach is reached even after twelve months for the hair on the head, and this is transferred in Pitchei Teshuva, Yoreh De'ah, Siman 344, Subsection 4, as law."