My 88-year-old friend has dementia. He has stopped eating and hardly talks. They have stopped physical therapy because it does no good. He still recognizes me, but he has no quality of life. It's like he's just existing and he is shrinking before my eyes.
However, you being just a friend have absolutely no say in this situation, unless of course you are his medical POA.
Hopefully he has a family member that is his POA, who can get hospice on board sooner than later.
Best of luck with a difficult situation.
If you are not POA, as a friend, none of this is in your control.
A person with dementia needs someone caring for him as either POA or guardian. The decision as to palliative care falls them to the POA/guardian and the advance directive or wishes of the patient himself.