My Step Dad Just Found Out That He Requires By

My step dad just found out that he requires by pass surgery again. His first one was 13 years ago. The surgeon told him because they used all the available veins the first time surgery is no longer an option. In addition he was told that his arteries are 100% blocked on both sides and only the one located in the back of his neck are open. I have never heard of this before. Does this make the heart work harder and if so how will this change his quality of life.