I know many would consider it a "failure", but Bob also retired into a job market where anyone who wants a job can find one. That means he should easily be able to pick up part-time work at at florist, which ties into his gardening hobby. Or temp work doing taxes in Feb.-April which uses is accounting background. Or if he was an [insert skilled labor description here], he might even be able to consult, go back part-time with his employer, or something similar. Or substitute teaching, where he has an entirely flexible schedule and can maintain his Tuesday pickleball game (good for his heart!) and the month he spends living with his son, Bob II, and daughter-in-law and playing grandpa. Or several of these. Bob should be able to quite easily $10k+ per year, reducing Bob's necessary withdraw amounts by perhaps 25%. And while doing work that doesn't tax his questionable cardiac health any more than chasing around Bob III and his sister Susie. (Also, this year Bob can scale back somewhat on his gift budget for Bob II, Bob III, and Susie, giving them a family museum membership instead of a pile of toys.)
If I were Bob, I'd likely be pursing something like this, and wouldn't consider it a failure at all because some version of chill, not-unpleasant, part-time work during the early years if the market is shit is just one layer of my plan.
Unlike many retirees who have faced scary markets, Bob's is one where jobs are plentiful. And that's certainly more than nothing.