Welcome to the forum, @Mantoron 
Did you have him in a party and with the attack / defense banner placed, perhaps? 
Although we have idle hearthlings bug, anyway. He might have got stuck with something.
The combat music plays if there’s any threat nearby, so if you have aggressive goblins near your town, it won’t stop, I’m afraid. 
Ah, that must be this bug:
Players are reporting that they get many camps spawning in a short time.
If your game lagged so badly as to have to close it, you might have had some errors running on the background, or maybe too many goblins. If you could paste here the contents of your stonehearth.log file (usually it’s located on C:\Program Files (x86)\Steam\steamapps\common\Stonehearth\stonehearth.log or a similar route if you’re playing via Steam) it could be useful for the devs.
Or you could also send your savefile to support@radiant-entertainment.com, mentioning this bug report on the email, so they can check what was going on.