I was scared of this weakness at first, but it's actually not that bad. It's mid- to low tier, albeit a bit more dangerous in the more horror heavy campaigns such as Innsmouth Conspiracy.
First, try to avoid being reduced to 0 resources during your turn: [...] Upkeep phase: 4.4 each investigator draws 1 card. Once those cards have been drawn, each investigator gains 1 resource. So staying at even 1 resource turns this card into, well, an unlucky Rotting Remains. Our Bob wont like it, but he does start with 8 Sanity so he can take bit of mental anguish over his finances.
Now, a personal weakness like this kinda forces your hand abit when it comes to deckbuilding, because you can never afford to go too low on Sanity. You could include an Cherished Keepsake but Bob really like the card draw from either Lucky Cigarette Case or intially Rabbit's Foot. You might want to invest in Relic Hunter early, or you could go for Peter Sylvestre as your first ally. He'll keep you sane enough to handle Greed when it hits (as well as boost your mediocre Agility score).
Eventually upgrading the deck into a big money-Bob deck will neuter the weakness completely. So that's certainly an option, and it feels like that's what Bob himself would have wanted. But there's lots of ways to soak Horror in this game; you just need to plan ahead a bit.
Last, Greed reminds me of Harvey Walters' Thrice-Damned Curiosity. Harvey's curiosity punishes him for having lots of cards on hand. Bob's greed punishes him for spending all his cash on items. And both feel a bit contrary to the character designs.