I suppose you are speaking from experience at your own child's funeral. If so I am sorry for your loss. But if not, then this is what I find unfair. We don't know how we'd really act. Especially in a situation like this. We don't know what we'd do or say. I know what I'd like to do. I know how I'd like to act but having never been in this experience I find it unnecessary to even voice an opinion on the matter.
In hind sight if we find out she had some involvement, that's different. But for now I think it's inappropriate. IMHO.
As a matter of fact I did lose a child. My mother lost two. All very young and natural causes.