DP's brother and SIL have an 11 month old baby, but won't visit family because the baby doesn't like the car. Since the baby was born, they haven't spent a night away from home or, in fact, taken the baby outside of about a 5 minute radius from their house by car (doctor, church, playground, baby group). We asked if they thought she would get used to the car at some point, but they said they thought it would be at least 18 months before they took her anywhere. DP's parents live 2 hours drive away and SIL's mum lives 3 hours away. When the baby was younger, people obviously didn't mind travelling to them. But now the baby is older, it's starting to irritate us and the rest of the family that they refuse to travel. AIBU?