Hi, there.  I'm not a psychologist, but I did raise two sons and grew up in a strict and rigid home and I would say yes, your granddaughter should have friends.  I'm not sure if you're saying her only friends are at school, or if she only socializes at school.  The first case might not be that concerning, but if she's not allowed to socialize outside of school, that can cause some real problems, I think, to her social development and self-esteem.  Your daughter probably thinks she's doing a good thing by protecting her kids from whatever she thinks is "bad," but the real world isn't like that and too much sheltering just leaves kids thinking either that the world is all safe or that there's too much evil out there and they're not capable of handling it.  Some day, they could end up rebelling big time, once they realize how limiting their lives have been.

It's hard being the grandmother, isn't it, to know how much to say and when to bite your tongue?  Maybe you could get your daughter to talk to you about her childrearing philosophy and how she arrived at it.  It doesn't sound like you probably raised your daughter that way, so you must wonder where she got this message from.

If you are in a position to be a support for your grandchildren, to give them a realistic view of life and the world, that probably could be very helpful.  I think there are a lot of people, myself included, who feel their grandparents were a very positive influence on their lives.  I wish you all the best.