My longtime player is quiet quitting
I've been DMing for my table for about 6 years. We were in-person for about 2 years, then remote for 4 after folks moved away and life happened. We play every weekend, typically Saturdays, for 3 - 4 hours. Discord for voice/video, Foundry for the VTT.
One of the players, a longtime childhood friend, has really withdrawn the last year or so. Camera off, has no clue what's going on during the session, couldn't say what happened a session ago, etc. Clearly just on his phone doomscrolling throughout the whole session. Things came to a head last week when he made some poor combat choices and two players died. In the post mortem, it was clear he had no idea what was going on - he didn't realize other players were down, he didn't realize the enemies were strong, he didn't realize he was the only healer still alive, etc. We had raise dead spells, so the players came back without too much issue, but everyone was annoyed that his lack of engagement was affecting them directly.
I've spoken to him about his lack of engagement. He throws everything including the kitchen sink at me. Dude says he's busy and overwhelmed with life. His job doesn't fulfill him, he suspects he has untreated ADHD, he's going back to college to try and get a degree to pivot his career, his wifi is bad, when people talk at the same time he can't keep track of what's going on, when he gets home from work he wants to get stoned and unwind, having a TTRPG session scheduled means he can't do other things (doomscrolling) and that stresses him out, etc. It is very clear that he is depressed.
At the end of this conversation, he apologized for his lack of engagement and acknowledged that it was unfair to the other players and to me. He asked to decrease his attendance to biweekly or once a month. I have no interest in him remaining at my table and no enjoyment from playing with him as-is, but I don't want to give him the boot or even encourage him to scale back when he's clearly in such a bad spot.
My wife, also a player in the campaign, believes strongly that he should increase his engagement. She wants him to attend the sessions weekly with his camera on and to be engaged, as a tether to socialization and his friends.
The Actual Question: How should I handle a player at my table who is depressed and bringing everyone else, myself included, down?