It is quite difficult – and, honestly, Gheer is probably irredeemable anyways – but it is in moments like these when I have to remember that Gheer seems to have both abandonment-anger issues and a deadbeat father, causing him to view everyone as annoyances to be exploited for personal gain. In his own words, "garbage sticking up for more garbage." Because of this, he can't stand the idea of affection, or being held back by someone at all: even Nona clinging onto him in Chapter 17 made him show his irritated-at-people face.
It takes not being okay in the head to pull out Nona's needle like that. It takes not being okay in the head to dedicate yourself to searching for two people who have done nothing against you, really.
In a way, Gheer is the opposite of Raloud. One is searching for family, and the other really cannot stand the idea of family.
This has been set up since Chapter 13, when Gheer reacted to Belator asking: "Even a guy like you must have a person or two who'd be sad if you died, right?" Hopefully, the writing of future chapters take this in an interesting direction.