@janbb Helpful is a great point! I think a lot of people who are younger were not taught to be helpful, like offer to help in the kitchen, help clear the table, or help dry dishes, etc.
If they all take one car out to dinner the OP can offer to give his father the front seat if her boyfriend is driving, or to sit in back with his mom, or hold the door for his mom if it is appropriate (If she is much older) and she is on the same side of the car. I know that all sounds old fashioned probably, but I don’t see anything wrong with it. We don’t know anyone’s ages.