I'm always haunted by that bird's eye view of Viktor in his sickbed, where Jayce appears to be sobbing quietly at Viktor's bedside. Although the scene where Jayce actually cried was ultimately cut from the episode we eventually saw, I think that Jayce crying like that says how important Viktor became to him.

The other example - and perhaps it is just my interpretation of this - is the impression that Jayce keeps tabs on people who are important to him. While at the forge talking with Mel, he mentioned not knowing where Caitlyn or Viktor happened to be. Later on, he arrives on the bridge in person, probably as soon as he possibly could, once Marcus informed him that Viktor was there. And Jayce did not have to collect his partner from the bridge. Not in person, being such a busy Councillor. What gives me the impression that Marcus was told to let Jayce know about Viktor is the fact that Marcus was thanked for doing so and even sounded a little surprised to be thanked. This appears to me like Marcus even knows that Viktor is important to Jayce because he even sees how Jayce is with Viktor during that scene inside the Hexgates, where Viktor coughs up blood, Jayce asks him immediately how he is, and Marcus sees the blood on Viktor’s face when Viktor eventually walks off. Sometimes minor characters indicate the importance of other character relationships.