A Nile cruise suits multi-generational travel well, mainly because the format balances activity and rest — guided excursions in the morning, then a relaxed sailing afternoon that works for grandparents who want to rest and grandchildren who want the pool, without anyone feeling like they're missing out.
Why the history itself helps
Egypt's ancient history tends to genuinely interest a wide age range, from young children fascinated by pharaohs and pyramids to older travelers drawn to the depth of the history — one of the rarer destinations that doesn't split neatly into "kid stuff" and "adult stuff."
The main planning point is pacing and flexibility: discussing which excursions are optional, and making sure cabin categories suit different mobility levels within the group, helps the trip work smoothly — see What Should Older Travelers Know Before a Nile Cruise? for the specific considerations at that end of the group.