You can't "make" anyone do anything. Have you tried sitting him out on a comode. Bedpans are pretty archaic and very difficult to use especially for the elderly who can not balance well. Many men are not able to use a urinal lying in bed they have to stand up. What kind of help have you sought apart from asking us?
Yakkeybarb, if he does not eat, he will not be able to poop. What comes out is only produced from what goes in. Hospice is fully covered by Medicare. Call them in the morning.