My SO suffers from panic attacks out of the blue where his chest feels heavy. A few times he woke me up feeling like he’s having a heart attack.

How do i help him cope with anxiety and what are a few tips for grounding or getting to the root of his anxiety?

I ask him whats bothering him sometimes but even on a good day or while eating and enjoying something he gets the heavy chest feeling he has a hard time breathing and palpitates. It is just so random and not even in a stressful situation, probably something deeply rooted?