LMo, I hope you forgive me replying this one time.

My dad had the same :Grade 4 - glioblastoma multiforme (GBM). This type doubles in size every day. My dad went ahead with the surgery, and it gave him 4 more weeks, a total of 5 altogether.

Say what you need to with your dad. I was the only one in the family that let my dad talk about death and his own funeral. It seemed to relieve some anxiety of things he wanted to say.

IDK if your dad is a man of faith, but even at this time, he might appreciate a visit and a prayer from a minister.

My heart goes out to you. I'm so sorry to hear this news.