Yes, you can help people recover, just by being a good friend.
“In a study published in Psychiatry Research in May 2017 researchers followed a group of more than 175 people who had experienced an episode of psychosis for two years and compared those who recovered and those who did not. More frequent social interaction with friends predicted a greater likelihood of recovery. Their analysis showed this was not just a result of pre-existing social relationship. The friendships provide both practical support and emotional support.”