Upon meeting your Muslim brother, call him by a name he loves and greet him with a smiling face.
"To smile at your brother is charity."
Encourage him to speak with you, or in other words, give him an opportunity to talk to you about himself and about his life. Ask him about his affairs, but only about those things that won't cause him
"Whoever is unconcerned with the affairs of the Muslims, is not from them."
(The believers, men and women, are Auliya [helpers, supporters, friends, protectors] of one another….) (Qur'an 9: 71)
Don't blame or remind him of his past errors, and don't cause him discomfort by making fun of him.
"Do not dispute with your brother, don't make fun of him, and don't make an appointment with him and then not show up."