Four Family In New Jersey_ Regulation Question - Please Help!

[Jennifer Vergeon]

Hello All! My dad owns a 4 family in NJ and has tenants who are on a month to month (no lease ) agreement. Some of these tenants are presenting issues e.g. they are backed up in rent, not paying on time etc.  Can’t he just decide to give them a 30 day notice to move out?? I thought he could do per NJ tenancy laws; however, we’ve been told he cannot since it’s a “4 family”. What is uniquely different about 4 families? Which NJ regulation says he cannot do this ? His current attorney also has not been helpful with this- does he need another attorney? I’ve spent an inordinate amount of time researching the answer to this question and have been unsuccessful. Please help. Thanks in advance.