Yeah. Ok. So, with Casper, that tie to the therapist is not something that he can make use of in any way. He's never met her. The nature of that connection will be revealed later on, but it gives him none of the access he'd need to have to make that reasoning work. His only other point of adult input is a dad who has already been stated to habitually beat him. There is absolutely zero trust there. He did the smartest thing he could in the confines of the situation. Sought help from a friend he trusted. James, on the other hand, is justifiably worried that anything he says will be either discounted as a nervous breakdown or, if he demonstrates that he has powers, might result in him getting turned over to some shady government basement for experimentation. He's justifiably paranoid because basically all superhero media he knows of has told him that it's better to keep his powers on the down low.
Even if he did tell his dad, he has no reason to believe the man could actually do anything. He thinks the dude's like, a real estate agent or something.
As for Tasha, yeah, her behavior is dumb, but it's very much supposed to be. She's a very reckless character, who tries to solve every problem on her own. I'll give you that one, hands down.
Like. Don't get me wrong. I can see your reasoning, but character perspective does play into their decisions. And the fact that half of these were choices made during a blind panic. Cuz, as you say, even a five year old would realize they're just digging themselves deeper. And that is a very easy place to start panicking and making rushed decisions.