When my spouse was dying, he continued to do as much as he could, especially the things that involved helping his supervisees, up until 2 weeks or so before his death. He did not feel obligated and very much could have passed this work onto other people, but he wanted to be able to think about something other than the latest crisis (his illness was short, from diagnosis to death a little over 4 months). From my experience watching him, he only did the things he wanted to and he didn't want others to focus or really even mention his medical issues. So I would say that if your T wants to work, it's because she wants to and she's not anticipating that you have to do anything different than you've been doing. Scheduling might become more complicated, however, if she has to accommodate more medical appointments.

I am sorry for your loss (and for me, the loss of anticipating my spouse's death was more profound than the death itself), but I also think that working with someone who is dying offers opportunities to discuss or simply observe that death is not so scary and can be handled with dignity. Silver lining and all that.