I have seen officers of my guild do the same thing. They do have families and lives outsides of guilds. In fact the last two years I have missed so many meetings and I really feel bad about it. I have had several health issues and that has kept me away, but I do contact someone from the guild to see if there is anything I could assist with. Maybe someone need to invite her to coffee (or some invite) and just socialize with her. You may find there is something that is going on with her. It could also be the time to present your concerns for not supporting the group and ask if she would like a replacement for the remainder of the year, if she cannot complete her responsibilities. Good luck and just remember there may be a good reason that she is not sharing.