Not going on vacation…?

So we are booking a “last minute” vacation for 5 days. My BIL had idea to go together including my in-laws and our 3 small kids. My husband and BIL would be driving separate cars, as destination is 6hr drive. As my BIL predicted, my FIL would rather stay home for his POOL! Than come out with us. My BIL decided he’ll stay home so my in-laws could go so he can take care of the POOL! Hubby saying no, because he says it’s to risky letting his retired parents drive so long. We have a cat and we’ll let someone in the family come over and cats-sit. How bizarre is this?? Husband is totally shocked and finds this a little selfish of his father. We are going regardless, it’s just never heard of someone choosing their pool over going on vacation with family.

Edit*

FIL would go if BIL stays to take care of the pool.