Our new kitten

Our son has been a trainee for the last few months at the so called "Wetterskip Fryslan" (organisation who looks after the condition of the water). One day, in the middle of nowhere, he found this little kitten behind the fence of one of the installations they had to control. Apparently dumped by his owner, because there wasn't a house to be seen within a mile. She was very skinny and hungry, so he decided to take her home, not knowing what else to do. He first wanted to bring her to the animal protection but later on he decided to keep her and to take her with him once he leaves his parental house, which may take a few years.
But I'm glad that he, and so does his sister, like animals so much that he couldn't leave her be.
For that I really don't understand why certain people do this to animals
On the picture she is outdoors on a rope, with around her neck a wristwatch. That was the only thing available as a leash.