Be the best friend you can and actually show care.
Uhm well you could hold hands/cuddle/smosh together(like a hug but tighter and more like idk these are just what I would have liked and also tell him your there, not to much though. Oh and call him yours and stuff:D
Ohh sorry lol I just read she soo like edit this^
And idk about women they are different but I have like all my close people (few are guys). Soo well this is what I would have liked from my ex..
Just a suggestion..why not have him use the patch or e-cigarette,which may cut back on the cold turkey moods..cold turkey is not for everyone!
Ignore their moods as much as possible , they'll live through .
have patience, it's only a temporary situation right now and they really need your support. been there done that plenty of times trust me.
Just take a deep breath and let it go, move on. Don't take their anger personally. It seems like this persons quit is a little extreme though and maybe you suggest that they should try and understand your position too. You can support them by being a positive motivating figure in their life. It sounds to me like you should ask them that, sounds like communication issues.