How to keep a semi-comatose dog fed and hydrated?

My 7 year old border collie has a large untreatable mid-brain tumor and is in and out of consciousness but has been out all day and I can barely get her to lap a little water off a spoon. She will growl if the doorbell rings too but is otherwise unresponsive. She has done this several times the past week and suddenly snapped out of it (she dove into her dinner and ate great last night) but I need to keep her nourished in the mean time.She can't go under anesthesia to get a feeding tube and the vets (we've taken her to many-both conventional and holistic) won't help at all-they just tell us to put her down or that she'll eat and drink if she can. But we do not believe in euthanasia and refuse to kill someone we consider a family member, especially with no indication of pain. She's on 10 mg prednisone and many holistic treatments. I could syringe her the water and pureed homemade food but I don't want her to choke