Role Play? WTF?

So, I have this game where a canon character (not a major canon but still a canon) mun hasn't been online for about five days now. It's a board RPG so its not necessary to post everyday. However I have another player who recently joined with an OC but who has played the canon character before and has expressed interest in playing them at this game. Usually I believe in waiting a week before I begin to try to track a mun down to ask whether they are still interested in playing.

I think this mun has been online though we are not good enough friends that I have their AIM and I only have their e-mail, but we hang out in the same fandom places. However is this enough time to start asking or too late or too early? I wait three weeks before I decide a person is MIA but that's usually only if it seems like they lost their internet for a very long time and have no way of telling me otherwise.

Thoughts on the situation?