Is it permissible to boycott a friend or take similar stances with someone who has shown their malice due to one's success in life, in order to avoid potential harm from them?

The forbidden type of Muslim boycotting his Muslim brother is abandoning him for more than three nights without a legitimate Shar'i (Islamic legal) reason. This abandonment ceases as soon as one greets him with salam. If you greet your friend with salam and do not turn away from him when you meet him, you are not considered to have abandoned him, even if you cut off the communication and affection that existed between you two. Among the legitimate reasons for abandoning someone for more than three nights are: fearing harm and injury from him, and hoping that abandoning him will stop that harm.