I think all you can do is try to think of this as 'blessed silence'. The problem is that if you contact him to see if he's still alive, you'll just end up opening a can of worms and potentially a barrage of unwanted emails. Even trying to ask a friend could result in them saying "Nogood was asking about you" or them thinking you want to get 'involved' in his life again. After all, if you called that must mean you care.
My DH's silences only last a few days if he's disabled the Ring. If he hasn't I get motion alerts. But if he has I'm very chary of calling him when I haven't heard from him for just that reason. It just starts the cycle all over again.
I've set myself a mental 'timeframe' of 48 hours. If I don't hear from him AND there's no motion on Ring at that point I'd probably call for a welfare check. But we've never made it that far.
It looks like he went to the ER this morning (Ring Cam). I've decided I'm not going to call round to see which one. They can get ahold of me or he can call me. He was sitting on the porch when they arrived so I know he wasn't in dire straits. I'm thinking of this period as 'blessed silence' since I know that, for now, he's safe and being cared for.