What is an objective way to say mr Barker is going into everyone's room and upsetting the other residents?

To be more objective, start by sticking with the behavior you witnessed. How do you know that the other residents were upset? In addition, the Word "everyone" may be interpreted as exaggeration, even if it is true. So, how about, "Mr. Barker has entered the rooms of other residents of his floor without invitation. Some of theses residents have complained to the staff, have shouted at Mr. Barker, or have become agitated for several hours after the incident. These intrusions into other residents' rooms have resulted in less cooperation/support/social interaction among the other residents. Since these incidents have started, staff are finding it more difficult to engage the residents in recreational activities/have more difficulty with wandering and agitation."

Best wishes to you; your desire to chart well says a lot about your professionalism.