I think it depends on the situation, personally. I dont think he’d do it just because, but if Rump was needed beyond a doubt to save the EF from a time traveling witch or a whatever, ESPECIALLY if Henry and Emma were in life threatening danger, I think he’d do it.
Well yeah, if they knew that Emma and Henry were in danger and there was simply no other way, then that’s a whole different situation to what we actually got. He was determined to find a way back because the last thing he said to Emma and Henry was, “I’ll see both of you again,” and it kinda defeats the purpose of that if the way they can get back to Emma and Henry is by him dying. So no, he wouldn’t have gone through with it if he’d known that it meant giving his life, he’d have held off and found another way.