It's false imprisonment but, more to the point, one can buy a universal programmable remote garage door opener at any hardware store. Many people keep the code set to 0000000. There are also openers that can 'listen' to the existing opener and 'learn' the signal. You could also run this question by a police officer in the next town. Maybe the police would assist him in removing his belongings. Or he could apply, possibly with the help of a lawyer, for a court order or even sue them for damages. Talk to a lawyer in your locality.
