Doesn’t strike me that your concern is anything other than commendable.
You see no evidence of any activity at all? OGS ought to be able to tell if the person has made any accesses. OGS has e-mail address from when account is established, right. Perhaps OGS could send a message. Depending on privacy policy this may not be kosher. That was the case at KGS when I wanted to get in touch with a person who disappeared.
At DGS there was a user who knew he was dying and posted something about it. I had an opponent I had played for a while at KGS who was away for a while, came back not playing so much and rating going down. Turned out he had had brain surgery. It hurt when I was able to beat a friend who had previously been quite a bit stronger. He only played a few times a month and then stopped. I assumed the worse; at best he just got disgusted with the situation and quit.
