To everyone who posted advice I feel I need to update you all promptly when I came home as you were so quick to give me advice when I needed it. Sorry for length, I'm a rambler. (Drives husband nuts!!)
I went round with flowers (expensive big bunch) and Dil's and son's mail and asked if I could come in for a chat.
I brought up that listening to my friends talk about their relationships with dils had made realise I had made grave errors with her (So I didn't drop son in it for telling me what dil had said). She looked uncomfortable and said everything was fine. I insisted it wasn't & I needed to apologise unreservedly to her. I apologised for my harsh words and lack of support and wasn't asking for her forgiveness but I needed to tell her how sorry I was. It was hard eating humble pie, very, very awkward.
Dil said it meant a lot hearing that. That my lack of support and words had made her feel very lonely, her pregnancy wasn't important and that she felt she was married to my son but not a part of his family. She also told me that for the past year she has multiple health problems because of that pregnancy going so wrong. (Her doctor called it 'the cascade effect').
It made me feel awful to hear this. I cried and she cried. Dil didn't want me to feel bad at all, said she forgave me completely and said the issue was over. I said in the future I will think first before I speak. She said she struggles as our family is very opinionated and she doesn't want to rock the boat and tries to mediate & keep everyone happy as she hates arguments, but I'm now realising over the din of us arguing the point poor Dil gets drowned out. We chatted for ages and really cleared the air.
I think I've always been a bit intimated by her, she's very academic and driven and she's succeeded with turning son's life around where I hadn't and I felt by giving my opinions it made me involved. I also realised after spending time listening rather than talking with Dil, she's actually really funny when given a listening ear. She's not I who I would have picked for my dear son, I would have picked someone girly and up for a laugh like myself, (I'm prosecco and sparkles girl and Dil prefers libraries and a book) but I'm lucky, she's kind and good to my son and our family.
Thank you gransnetters for helping me fix this situation. I'm coming here for advice next time before I go to my friends. I'm also going to have a stiff gin because my god that was hard! Still cringing thinking about it.