My first suggestion is to focus on helping him with managing his pain. Saying he fears his emotions and the consequences of the potential actions he may choose is reasonable.
OFTEN times one needs to get the "OMG I'm afraid I'm going to do something really stupid" emotions off our chest and who better to confide in than our most trusted partners or friends.
I wouldn't focus on "dude, that would be unfair" unless it actually comes up as a "I think I want this" topic.
I know for me-one of the things that really helps me to manage my anxiety (which is a little different) is to be able to express fear of what I may feel I need to do if the anxiety gets worse. If I can express that fear-sometimes that alone releases it. Always it reduces the power of the anxiety.
"Love As Thou Wilt"