One of my coworkers has been off for weeks with mental health issues. He's been in for a week then off for a week consistently since end of lockdown. He's recently returned and is extremely quiet with anyone apart from the manager. Its causing an atmosphere and I've tried to be respectful of their needs as I dont like the idea of making him feel uncomfortable coming back. But he's made it so uncomfortable today that you could cut the atmosphere with a knife, it actually brought a dark mood to the team. Hes sat staring at nothing not speaking to any of us, until he's left alone with the manager. I dont know how to reach out to him and keep a positive attitude for myself as I dont want to become gloomy also. What tips do people have in helping me support him and make it easier for everyone?