I enjoy her wit too, which is evident in other things she says to Marianne during the very conversation of which we're speaking.

I just don't think that particular statement is any other than gentle kindness to her sister . First I think it is too gentle to be obvious, so if she slyly meant Marianne not to understand, she would just be venting for her own satisfaction. I'm sure she gets tired; I just can't imagine her attacking(for lack of a better word) their expressions of grief with her wit.

But we can feel free to laugh about it. :-)