It's been said to death but your mental health does impact your physical health. Bob's undying anger creates unneeded levels of stress and that stress makes any pre-existing conditions worse. Did you know stress can kill brain cells? We've already discussed Bob's refusal to really work that muscle in his head so maybe he won't notice his shrinking grey matter. If his weight is a sore issue for him, it's also nice to note one of the hormones your brain releases while stressed is linked to weight gain.
"Laughter is the best medicine" might sound like corny advice people give the ill but there's truth behind it. Seek help. Constant pessimism might as well be a poison.