ANSWER:

No problem in joining them and performing your prayers on time even if you have to disobey them in this regard. Your presence might be a deterrent for them from doing a lot of more sins and you might also be a reminder for them to pray on time. 

There’s no obedience to the created at the cost of disobedience to the Creator.

sheikh, my family go out to far places sometimes for the purpose of enjoyment and they are not practicing and careless about the salah and I fear that if I go with them I would miss my salah and would be difficult for me to pray and I have to disobey them in this regard, is it permissible for me to disobey or should I go?