"what is he to you?"

--
this scene is interesting to analyze for various reasons.

firstly how calm Bonehand is in this comic. like you'd expect he get angry and jealous if he hear that his cousin is in love with Panda. but no. He's aware how serious the situation is.

because Ugly Cat loving and caring for Panda as a family is one thing, but romantically?

putting aside how fucked up that sounds, BH saw what happened when his cousin was in love with Jane many years ago. He saw how badly it broke him when he lost Jane. He's worried it will repeat again.
He's not sure if he can ever get rid of Panda knowing how it will affect UC.

and if what Panda says is true, it might means UC never truly moved on from Jane. He's confusing his grief, loneliness and need for romantic affections and projecting it towards his own adoptive son. This is a real concern.

How does Panda feel? like BH asked, what is UC to him?
Panda only sees UC as a father figure, a quite abusive one even. But he also likes it when UC is being nice to him, so he doesn't particularly dislike it when UC did something beyond that.

but it's making the boy all confused. so there's no right answer. between a father, a 'lover', and abuser... He don't know how to process this.
so he risked confiding it to BH, the person that despises him the most but also the only person that knows UC well. this scene here is a moment of trust.

and I like seeing this side of BH+Panda... who are supposedly rivals/enemies but this time they take a moment to figure it out together because they both care about UC. He's the center of all their problems but also a bridge between their relationship if you think about it.