According to IRS, it allows for a single tax-free rollover of a 529 account per beneficiary in a 12-month period. This 12 month rule should not be violated because it can result to a 10% penalty on the earnings. However, transfers across siblings are not considered rollovers.
Bob is just a human like us and feels stuff, its probaly due to his environment and pressures/stress but heck who really knows. Bob is Bob. and that is that.