I read this phrase:

"...the solace of female tendance for his declining years"...

and looked up 'tendance' for a more precise definition than the one I'd assumed from context. I'd assumed 'attendance' was related (correct assumption), but not exactly.

'Tendance' was a shortened form of attendance, but the definition was specific with 'watchful care,' which I like very much.

Despite thousands of Google hits that I didn't check out (!), the first three pages of hits were mostly French. Even with an advanced search supposedly in English, I still kept getting French usage of 'tendance.' It doesn't appear to be a word with much activity. (I wonder what the linguistic term is for active words?)

So, I wonder whether 'tendance' is a word that is going by the wayside with 'attendance' taking its place, both in carrying out those deeds requiring 'watchful care' and those that are less caring.

Too bad, if so. It is a lovely word and concept.