Okay, this is going to sound very unpopular but just hear me out. LOL
DO NOT comfort a dog that is afraid. Don't coddle him, pet him or otherwise try to "love" him better.
Why not? For the same reason that you DO pet him when he does something good: you are telling him that whatever he just did is the right thing to do! So when you pet him while he's panicking in a storm you're telling him he was right - he SHOULD be afraid!
Instead, you need to be calm and confident. Lead by example - project the idea that there is nothing to fear, and that you are in control of the situation. You aren't going to let anything bad happen to him, but you can't tell him that with words or petting - instead, let your body language and energy tell him that.
As tough as it is, you have to ignore the behavior you don't want. In this case, I would put him in a sit or down position next to you, silently project your calm confidence and read a book or sew something. As long as he is sitting where you asked him to be, ignore him until he calms down - THEN you can praise him, thereby reinforcing the relaxed behavior.
No drugs, no feeling sorry for him. Instead help him face his fears and get over them. It isn't easy and it won't be instant, but I promise it's well worth the effort!