why does Tyson act to needy when confronted with affection?

Good question, no one. Let’s start with Tyson’s childhood. His father never gave him any affection which meant any he got came from his brother and mother. His mother and brother abandoned him when he was young meaning for a long time of his life, a time when affection and support is incredibly important, he got none.

Then he joined the army and (almost) the only affection that he got came from Sebastian, hard to believe but on occasion Sebastian was nice to Tyson. By now you should notice the theme, Sebastian also abandoned him (after months of abuse.)

This means Tyson is both deprived of affection and afraid of it. He desperately wants it because he’s been starved of it, but at the same time he’s afraid to have it because he’s afraid that it’ll disappear if he has it. He clings to the affection so much because he’s afraid that if he doesn’t hold onto it tightly it will disappear and leave him like everything else, it’s why he doesn’t let Lily and Bobby out of his sight.

Tyson's handwriting

His signature (below) is generally much neater than his handwriting and is closer to how his writing looks when taking his time and being extra careful, such as when writing on his maps, as opposed to his general/note taking writing above.