Well, my son has brought the kids up, whilst his wife works, being the higher earner. There is also a cultural difference. I spend time on skype with my son and we discuss all sorts, including how the kids are doing. My son's mother-in-law lives locally and is quite a character, but it is accepted that both my son and his wife do their own thing. I am perfectly happy with that, and as one of my grandchildren has special needs, I am more than comfortable with their choice of developing his education.
The thing is, I really have no input on their chosen life, nor how they raise their kids, being so far away, apart from our conversations. I do trust, however, that my son's influence aligned with his wife's culture, makes for an interesting mix.
What I am most pleased about it that they so happy together - they have fun and so do the kids.
OK - so maybe I would chose to have more boundaries, but there is a freedom for the children which I embrace.