I feel I may be going out on a limb since I don't really know the family dynamics. But I do know that if your treatment plan includes chemo and radiation, your husband may not have the time or the energy to deal with the daily chores, especially if he is not domestically-inclined. You probably won't be able to do the chores yourself after a couple of weeks of radiation. So, some help in that department will be needed. If you could talk your husband into getting his brother to come at the time when he is really needed, then do so. (Treament won't start for a couple of weeks at least after you've seen the oncologist, so it makes sense for him to allow you to take a breath and plan which scenario you would like.) If not, see if you can set up a space for yourself (in your room/the den) where you have everything you need and you can close the door on the drama that's going on outside.

As for the young people, I hate to say that, but emotional blackmail has worked for them, right? So, I would just ignore the sob stories and let them go on their way.