Oh hun. Definetely have him checked out.

I know how you feel about those words. My BIL is an amazing person, but so many people don't care to see it, or they use it to their advantage

Do you still wrap Kat firmly? If you're worried about sensory issues, maybe she's like Bri. Bri is a seeker. She prefers tight clothes, tight shoe laces, tight hair etc & stresses to the point of howling if they aren't tight enough ()
Bri is a big movement seeker as well. Maybe Kat likes to move & a swing would help? (just going off the things I've read from you on fb). Bri was the hardest of my babies. Screamed for hours on end. She really wore me down. By the time she slept I was the one crying

Talk to your health nurse or gp. They'll help you with OT/paed etc.