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. We ask Allaah to exalt his mention as well as that of his family and all his companions.
Since the person you referred to in the question is performing the five daily prayers, and performs the recommended acts of worship and other religious obligations, like growing the beard, then this is a good act for which he should be thanked and this is evidence that he is on much good.
As regards him harming other people, if this is confirmed, then one should solve this deficiency in him with wisdom. There is no doubt that if a Muslim harms his fellow Muslim brothers, then this is a sin from which he should repent. Harming other people is very serious for him in this world and in the Hereafter. Allaah Says (what means): {And those who harm believing men and believing women for [something] other than what they have earned [i.e. deserved] have certainly born upon themselves a slander and manifest sin.} [Quran 33:58]. The Prophet was asked about a woman who performs much supererogatory prayers and fasting but she is verbally abusing her neighbours, and he replied: ''She is in Hellfire.'' [Ahmad & Al-Haakim]. Therefore, the matter is very serious.
Similarly, considering oneself as superior to others is reflects pride. Thus, whoever has this characteristic is obliged to repent to Allaah. Whoever knows this person should remind him of Allaah and explain to him that he is in a very serious situation as he is harming and humiliating other people. However, one should advise him with wisdom and in a soft and tender manner.
For more benefit, please refer to Fatwa 88745.
Allaah Knows best.