Lola, I don’t believe you are being selfish as 4 hours is a long drive and down the road you may be needed more urgently for something else. As long as your Father and Sister are going I think that is fine. My own personal opinion. A PET is a walk in the park. Don’t know if they will know the results right away. That is when you don’t want your Mom to be alone as more than one set of ears is best to help take it all in. Good luck to your Mom.