Atm, Tav sometimes interjects "I'm tired. I need some rest" but it can get covered by ambiental sounds or interrupted by other ingame events.
The entire party says it every now and then, but there's no genuine tiredness/exhaustion mechanic in place to make this a thing you should actually care about.
IF that's supposed to be your cue "Do a rest and we'll have some dialogue" then it's a terrible implementation.
