"I understand" - no you don't
"I can imagine" - no you can't
"How are you?" - you don't really want to know
"Are you ok?" - what do you think?
"I lost my grandfather/uncle/etc." - doesn't fucking compare
"At least you had him for..." - how long is enough with YOUR kid?
"He's not hurting anymore" - should never have been in the first place
"You're so strong" - I have no choice
"I couldn't do it" - I want to die every single day
"But you still have M" - and that makes it better you fuckhead?
And so help YOU, if you come at me with "God has a plan" or anything like it, I will go off on you. And quite possibly hurt you. And not feel a damn bit sorry about it.
So what should you say? I'm sorry followed by a hug. Because no words can make it better.