I am so sorry to hear how you are struggling. It sounds like you are getting top of the line care. But still the anxiety of the unknown can be daunting. I have been dx with a rare thyroid cancer, and was told on its return that it was terminal, 30 yrs ago. So much for terminal ! I
was dx with one rare form of renal cancer in my right kidney and then three months later another form in my left kidney. Both operated on and reconstructed. I have stage 4 CKD now and have had sepsis twice which affected my heart... and now have heart failure as well. I tell you all thus just to let you know I get it!

Best advice I can give from my perspective
Live you life each day. Fully and ... fully present!
Capture the good moments and give yourself grace in the hard moments.
Spend time with those you love anyway you can. Your legacy is what you are living out right now with those grandchildren. Tomorrow is not a guarantee for anyone really... it this moment we have .
Be in it! Present!
Sending you love. Prayers and big hugs