my mom is pushing a guy on my sister

My sister turned 16 in December. The guy turned 23 not to long ago. She likes him and i guess he likes her. But it is weird to me, to him we are the little girls across the street that he watched grow up.
Here's how thier relationship is: casual flirting only verbally but he comes over and watches scary movies and they sit together and hold hands. They talk alot outside the house and thats about it.
But my mom! She loves the guy and first wanted my big sister who's almost 23 to hook up with him and now she is moved out with her boyfriend and now she's pushing my 16 year old sister on him! She always tells my sister when she sees him outside and always tells her to invite him here and there and she says stuff like "Look at her hair, its pretty huh?" and damn, its like she's advertising! My dad says the same. But this really bugs me cuz i strongly disagree and think my sister should be with some one on her level. But what do i do? I have talked to her befor about it and she agrees about my mom but when i talk to her about the guy and her wanting to be with him, she just gets quiet. What should i do?

My dad does the same thing, he goes out soliciting dates for me, "This is my daughter, she's hard up for a date..." and I want to kill him.

Anyway, parents shouldnt do that, it is one thing to be supportive and it is quite another to be pushy, not to mention that the age difference in this situation is a HUGE one, developmentally those are BIG years.