First he needs to file grievances and exhaust his administrative remedies before filing suit. He should go to the prison library and get a copy of the Prison Litigation Reform Act. Here is a link.
The grievance needs to be specific about his complaints.
After the grievance procedure is exhausted, including appeals, he can then file suit.
My answer is the same I as the one I gave you last time you asked. Now that you have identified the facility, I will add that the cleaning there is done by the inmates so, if it is filthy that may indicate an inmate problem rather than a State problem. I know it was OB for a short while but I was in the units five or six years ago and did not see anything alarming. And, believe me, I was not on a "VIP" visit.