Your frustration and maybe even resentment are understandable in view of what you see as the unfairness of you having to limit your visitors when it seems the foster carer did not.
However, as the grandparent of an extremely premature grandchild and as a former social worker who worked in adoption I have to say that I believe the social workers are simply acting, as they are required by law to do, in the best interests of the child - as they see it. There is now a substantial body of research about extremely premature babies and potential problems they may have with bonding. Most SWs worth his/her salt will have done their homework on this in order to understand the issues. (I did my own research on this when my granddaughter was born.)
Three weeks is no time at all to set up a new routine and get to really know your little grandson and your friends are always going to be available to you on the phone during that time if you feel in need of a bit of support. Try to let go of your frustration and accept, if you can, that you and the SWs both want what's best for baby - even if you maybe won't always agree on what that is.
I applaud your commitment to your little grandson and wish you joy as you welcome him into your family life.
NEVER EVER HAVE I - Game 2 (Alphabetical)
What do you think would go well with coasters like this?
To go through chemo therapy or choose not to?