Do you think Leona was a little too nice and forgiving to Jun? The first time she ever saw her, she robbed and attacked a man. Plus her actions could have gotten herself and her son killed.
Took me a while to see this ask, sorry!
Well, Leona could have chose to not help her, of course. But considering she lives in a city full of vets abandoned by the government, it's not surprising for her to grow empathy for them and choose to help.
It's a delicate situation. Most vets are physically disabled or at least mentally scarred from the war. A lot of them came back with nothing, and the rest of the town has a pretty split view on veterans, some part seeing them as scarred struggling individuals, and others as arrogant self-entitled heroes supported by the government. Even though there will always be people like Leona to help, there will always be people who overlook the veteran's struggles after returning for the war, seeing them as privileged (which as we can see, it's not true, most vets are disabled and suffer greatly from PTSD).
Jun is definitely not the only vet stealing to survive, and I believe Leona has seen enough to come to a conclusion that there is no point on not helping someone who has nothing to fight for aside from survival. PTSD is a story about overcoming your traumas and your fears and accepting help. I fully believe it wasn't Leona's responsibility to help Jun get back on her feet... But the government failed her, society failed her. Leona just did what felt right to her, even if she didn't owe Jun of anything.
In the end, Leona chose to give her a chance. And probably without that chance, Jun wouldn't had overcome her initial struggles. It's a very brave and kind attitude from Leona.