Its possible that the $300, pot and gun had something to do with it. If he just took the cell phone, I am not thinking we would hear about this.
Yeah this was an armed robbery despite the stolen property.
The elements you mentioned ($300., Pot & a Gun) DO complicate this case a great deal, and cannot be ignored.
However, he will always have the inward satisfaction of seeing the look on that thugs face when he ‘reclaimed’ his daughter’s phone. He will remain a hero to his daughter forevermore.