In some ways I am like your father. My wife had a GBM removed 14 months ago and I have been her caregiver ever since, sometimes being over protective. When my wife was first diagnosed with a brain tumor which turned out to be GBM I told my children that I would take care of the immediate needs, i.e. arrange for the operation, rehab, insurance, meds etc. and gave them the responsibility of gathering more info on GBM's, treatment programs, etc. So far that has worked out well. Perhaps you could offer to do this for your father. It would also be helpful for him to get some relief from the caregiving, if even for an afternoon. Hope this helps