Be a good listener and remind them that they will feel eventually better. Don't expect them to take on a lot responsibility or make too many decisions until after the depression has lifted. Watch for remarks about suicide and report them to their therapists. Engage Them in Constructive Activities - This could include taking walks and participating in activities such as hobbies, sports, and spiritual activities. While they need diversion and company, too many demands can increase their feelings of failure.
People can recover from depressive illnesses, if they get the right help.
None of these things by themselves was enough, in my case, to create balance in my emotional life. But taken as a package, they have each played a part in the restoration of my sanity and in making me a strong and productive part of the body of Christ.