Thunder shirts need to be used correctly. If you put it on after the first bolt, it probably won't work at least on many dogs. They simply associate the shirt with thunder.
You should put t on them randomly when it's not stormy and they will associate it with being happy.
Also don't comfort them or treat them like their wounded when the thunder comes. Again, association and thinking something is really wrong. Act normally.
Rescue remedy helped our standard. Our rescue Morkie that was raised in an outside kennel is having a hard time.