If it was MIL, I'd just say Thanks! See you soon.
But he sent me some info I'd asked MIL for as she was on the train. And he signed it "Have a nice evening. FIL"
Now if I write back
Thanks!
Have a good week
Does it look like I'm just repeating him? He's retired, not likely to see him until the end of the month.
Best wishes sounds too ridiculously formal for IL's . But it still needs to be polite.
Argh, what's the etiquette for IL emails?