This is a great idea!
Perhaps, maybe it would be really cool if there was a mini world that was a retirement community. It would have all of the events and you describe, but elders could be moved in there and live together in the apartments. Obviously there are some elderly that wouldn’t want to live there, but I could see the Gurus adding buffs and making the world an enticing place for elderly to go- especially for narratively driven simmers- i.e. an elderly widow going to the retirement community and finding love again, an elder abandoned by their family who finds their chosen family at the facility, etc.
Sims who have parenthood can show up their physically when they volunteer. Elders can be seen in the neighborhoods going to museums and admiring the art together, there would be a theater lot- either a rabbit hole or something- where elders can watch theater shows put on by the High School drama club, Sims in the entertainment career, comedians, or local drama troupes. Bars will have senior night discounts.