If they were smart, what they would do is sell them directly to consumers who will cherish them and give the paintings good homes. Then make the buyers sign a contract of some sort that they can't be resold for X number of years. That way the paintings bring joy and value to others, while respecting Bob's wishes of not being a commodity.
And then they would be involved in lawsuits with normal people who didn't honor the contract. Legally okay, but would be a bad look for the foundation.
