Avery No, she is not kidding. I don't know how old her intended is but it seems he is quite a bit more mature than you. He is marrying into a family, not taking it by storm.
Part of growing up is becoming independent from your parents and making your own decisions. Of course it is good to listen to what your parents say about important things in life. But the decision is up to you.
From what @ZeynepFox has written so far, her future husband will make the decisions. He has to stand his ground and clearly define what is his area. The mother cannot make a decision here, otherwise he makes a fool of himself.
Whether they are in bed all the time or do something else is entirely up to them. If the parents have done their education properly, they will certainly come to a sensible decision.