All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His Slave and Messenger.
May Allaah reward your boss for his enthusiasm for doing good. We advise him to continue helping people according to his ability. However, he should not miss congregational prayers for the reason which you mentioned. Rather, he should go to perform the prayer in the Masjid and then if some people get in his way to beg and he has probable cause to believe that they are not in need, then he should not give them anything.
If he has probable cause to believe that they are in need and has nothing to give, then he should refuse them in a gentle manner, as Allaah says (what means): {And as for the petitioner, do not repel [him].} [Quran 93:10] But if he has something to give them, then he may give them and he will be rewarded by Allaah – Allaah willing. For more benefit, please refer to Fatwa 85667.
He should know that the congregational prayer is an obligation for men, but it is not an obligation to perform it in the Masjid according to the view we adopt here in Islamweb, though performing it in the Masjid has a greater reward. For more benefit, please refer to Fatwa 92317.
Allaah Knows best.