Thunder Help

I've never been on here to ask this, but I need some help from Reddit! I have a 20 pound Havanese that is scared out of his mind by thunder. Last time it happened when we weren’t home, he cut his mouth on our metal baby gate, trying to get it open and then squeezed underneath it and tried to climb into the washing machine, then got into the closet and ripped half the clothes off their hangers and they were all over the floor outside of the closet, he chewed boxes and other things. He normally does none of this. He is high strung, but is really only afraid of thunder and fireworks. We have tried different fixes like the thunder shirt, tranquilizers and inexpensive head wraps all to no avail. For one thing we both work and we will not tranquilize him while we’re not there. I was looking at some expensive headgear, but want to make sure it works before I try it. Anybody have a good solution for something like this? Thank you.