Oh my!
I wish I could give you advice that would make it all better...but I have none. I could offer such platitudes as it was meant to be or it was his/her time or they're in a better place now...but that's just a bunch of bs. I know I wanted to slap people when they told me that when my grandfather died. I knew they meant well...but I really don't think they knew what they were saying.
All I can is is that I'm deeply sorry for your loss. No mother should ever have to go through the pain of losing her child.
((HUGS))