You've gotten some very suggestions so far, many of which I second.
However, may I suggest before you involve your DE and UC, that you have a talk with your charter organization rep? Who sponsors your pack? That organization has a lot at stake in the selection of a good CM. Do they know your current CM is unsure about his future in the pack? Are they aware of your willingness to take over?
Also, there's nothing preventing you from going to training now. I highly recommend it, even for folks who are in assistant positions (ass't DL, ass't CM, etc.). If you get trained now, you can step-in immediately in the current CM drops out.
Finally, you *really* need to get a new CC onboard so all that administrivia doesn't fall to you (and I'm not demeaning the CC job -- I am a former CC myself).
Good luck and keep us posted.
Fred Goodwin
(current) ACM, Pack 2003, Alamo Area
(former) CC, Pack 468, National Capital Area