Elderly doesn't equal dead, and you'd be suprised at how many of the + 50 crowd is using the web and social content.
It's so prevelant that they have their own Social world at
www.eons.com, their own search engine at
www.cranky.com and they are doing quite well.
While YouTube should not be the main focus of the marketing, it certainly isn't going to hurt them in any way or form. Distributing across all video production sites simply allows them to have great exposure.
YouTube offers a way to reduce his cost for video hosting and offer a little extra exposure. Won't kill him.
Regarding YouTube being slow, it is much more likely that his own server might load the video slowly than YouTube simply based on their size and volume.
I think that much of the advice here, especially those discussing to push the video through various sites are very good pieces of advice.
Too many times, people try and pigeonhole a web site such as YouTube into a certain age group or demographic and that isn't always the case.