Sad news. I watched last of, for the first few years & enjoyed it, but it went on for too long. But I recognise him. He was I believe, the husband of Kathy Staff in the series.
Before he found his niche in LOTSW, he was a very good jobbing actor and appeared in nine films as well as several TV series in various roles. 90 was a good innings, but the loss of his wife a few weeks previously probably sped his departure RIP Bobs.