It wasn't that Tron didn't understand losing people close to you but-
What?
Tron was visibly stunned when Clint asked about Fissure. He stalked across the hall, following Clint into the kitchen, blocking the doorway.

"Clint, Fiona, Dana, and Zeke have been missing for months." Even if he hadn't kept in contact with the team, surely he would have heard that much.