Positive for Covid-19

My fiancé recently tested positive for the virus, he’s in the military but he’s being sent home early. When he first started to show symptoms they put him in a 72 hr quarantine but tested negative the first time and was released from his “quarantine”. They tried to put him back to work last night so he was tested again to be sure & it came back positive. He was given the option to quarantine on the base but he’s almost positive that he got it during the hold because his room wasn’t disinfected before or after. He will be coming home so any suggestions on how to handle that? We have a roommate but separate rooms & bathrooms, Im already planning on cleaning intensively all the time but do you have any tips? Have any of you gone through this?