Alright, I'd be glad too, lets get started.
So lets go in order, and I will edit the story so this can better fit your questions and look more realistic.
His father, years of thievery. Well, we can say it was occasional and we can say he got caught a couple times, why not? Maybe on certain days he didn't come back, because he got arrested, thrown in jail a few days then released. Since it being a village, with little law enforcement. It would be quite easier to rob, his father was a plain criminal but did it for the good of his family. So I will go ahead and edit a few things, and maybe even add a new date for this one.
Next. His father was indeed shot dead in 2451, because of the ONLY gun he had. You're right, they were probably really unsupported. When his father died. Fhaai was pretty furious, so he worked out a lot, because he wanted to fight the war when he was older. Not some highly trained soldier, he wanted to be shooting guns, in the front-lines where his people needed him most. We can add in the story, that he would work small jobs around this town, for any money at all. His sister also would work for money as well. His mother is a little older, and kept this poor quality living space, where rent was practically nothing. They rummaged the trashcans during the night, for any frozen foods left over, maybe reheated then they would eat later. Trading could still be done, local trade markets surely existed somewhere. The family had possessions, a couple boxes of things, and the place they lived was nothing compared to the cave the lived in prior, only thing is better insulation. But no running electric or anything, basically lived in the Ghetto of this town, stayed hidden sort deal.
On Fhaais education and skills. We can add, that he didn't get any sort of diploma through a public education. But he did get one through Home Schooling, that his Father put most of his trading and money into. ALSO, to become a highly trained soldier, no college is required. Only mental capabilities (Which he had) and the Strength, only possibly a diploma is required. So he had everything needed to become a Kosmostrelki. So usually just becoming a Kosmostrelki is mainly hands on training, which Fhaai is really good at. He just isn't good at Knowledge tests, but he did enough to pass through. Much of piloting the Fang was hands on, and he remembered that knowledge and used it to pass. Much of his ability to make things up on the fly and improvise came from his Father, his Father was a thief after all. Now his desertion of the Kosmostrelki was also in reason with his knowledge, knowing that he isn't a good improviser, that he would probably fail and die in his first dogfight, hence his capture by Scrappers when he deserted. Due to his shackles or whatever restraints they had, he was unable to escape. A few Kosmostrelki were able to escape from this place on their own.
So this touched up on your questions.
We explained why the uneducated, impoverish zhan-khazan who came from bumfuck nowhere became one of the mostly highly trained soldiers in the PRA Orbital Fleet.
We explained why exactly does his family have an expert thief: his father. Not only did he manage years of stealing food, ammunition, guns, ecetra from villagers and soldiers, not once was he caught? Yes he was caught a few times, and only stole one gun to clarify.
We explained what exactly happened between 2451 when his father was shot by ALA forces, and 2457 when he began working.
We explained how the family was able to support themselves upon transitioning to the new town, considering he didn't take up any formal education in the six years since 2451 in war ravaged Adhomai, and thus lacked any formal skills it seems.
Any other questions? I hope this clarified some things.