I found out today after eating lunch there (didn't sense anything "off"), then stopped for dessert down the street at Cafe International where the owner told me Bob died last Monday of a heart attack while scuba diving.
I discovered Bob and Memphis Minnie's in the early(?) 1990s when it was on Polk Street (I think his second location). I recognized the quality of the bbq immediately, as did a visiting family friend with a masters degree in food service and an accomplished chef in his own right. I've been going to his Haight Street location since it opened, probably every three months on average when I would be close at the right time. The barbeque seldom failed me, and the staff always seemed dedicated, accomplished, and friendly, quite a feat to pull off for Bob. The staff obviously is dedicated to carrying on Bob's vision, and if today was a good example they're doing a very good job of that.