All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger. {C}
We advise you to be patient and compassionate with your brother, and strive to advise him in a wise manner. It is preferable if this advice is done by some relatives or righteous people whom you think can influence him and it is likely that he would listen to them.
You should know that pardoning the offender or wrongdoer is a good conduct that Allah loves and for which He gives a great reward. Indeed, Allah increases the person who forgives in dignity and honor. The Prophet said: "Allah increases the honor of one who forgives…."
Also, countering a bad deed with a good deed and saying good words (even if one is only pretending), is something that brings affection and prevents the evil insinuations of the devil. Allah Says (what means): {And not equal are the good deed and the bad. Repel [evil] by that [deed] which is better; and thereupon the one whom between you and him is enmity [will become] as though he was a devoted friend.} [Quran 41:34]
Al-Ghazaali said: "Courtesy, whether it is natural or pretended, breaks hostility from both sides and reduces its effect; it accustoms the hearts to be compassionate and loving; thus the hearts rest from the pain of envy and resentment." [Ihyaa’ ‘Uloom Ad-Deen]
Allah knows best.