I am so sorry you have to go through this. I know that dealing with all these things are very stressful. Your niece is probably grieving too, but still, the neccesary things has to be done, and a little help from her sure would be useful! When the most important things are over, you should simply take some time to relax, messy surroundings or not. Let her see that you just can't handle anymore, and she may realise that her support is needed.

(((((hugs)))))