I have a similar problem. Our current President does not get up for any activities anymore. She just hasn't wanted to, doesn't feel well etc. She does however get up for the resident council meeting but does not provide any input because she is never up for anything. So here is my plan:
Go talk to the president ask her why she hasn't been getting up. I plan to bring her the resident council book and explain to her that the president is someone who is hands on in the building, participates in activities, greets new residents, and is an active voice and listener for residents and what they want here in their home. I will ask her if she is still up for these responsibilities and if so then I need active participation and socialization with residents the next two months or an election will be held. If she says she is not up for the task anymore I will ask her to come to the meeting and relinquish her duties as president and an election will be held. I will ask the council who wishes to be the president and who wishes to be the vice president; write their names on the whiteboard; create ballots; and let the residents write down who they want and put it in the bucket to be counted. Thus a new president will be.
I would suggest something similar to your situation. Announce the duties and responsibilities to everyone in the meeting after your current president decides what to do and let the residents pick.