My cat gets scared of Thunder

My cat gets really scared of thunder/hard rain, he usually hides in the bathroom on the floor. But as of today he’s now hiding under the sink which I’m surprised he fits under.

But I wanted to see if there was anything else that could help calm him down or at least make him comfortable while the storm passes.

I was thinking about getting him his own cat cave.

I’m open to suggestions/recommendations, thank you