first time gran and nervous

After 3 weeks of sleepless nights they will be grateful for all the support they can get!!!
Once they see how proud you are of them and the baby they will be keen to inform you of every little dribble and burp.
I agree, don't offer advice unless they ask for it and when you visit try and help with a few practical things, like hanging out washing/get a bit of food shopping if you think they would find it supportive.
New parents are very sensitive and usually sleep deprived so make allowances if they are a bit snappy at times.
My grandsons arrival bought our family much closer and like so many people on this thread many of the anxieties never materialised.
Good Luck and enjoy this special time.

I was totally unprepared for the overwhelming feeling of joy holding my first granchild a few hours after she was born 8 years ago. I thought my knees would buckle. I think it was the best moment of my life.......you will know what to say and do whe the baby arrives......just enjoy every moment xx

You know what the bumper sticker says - "If I'd known grandchildren were so much fun, I'd have had them first". It's wonderful being a grandparent and if you bite your tongue when necessary that avoids many problems. Keep praising anything you can (honestly) about how your son-in-law deals with the baby and that should help. Good luck!