My 74 Yr Old Husband Has Been Unable To Urinate

My 74 yr old husband has been unable to urinate for the last 24hrs. He does have a slight prostate issue and has been taking Climax for approx a year. Has also started a previous med for the last week called Urocholine in the hopes it would help as it has progressively to become an issue. He doesn't want a Cath done, So have been unable to get him to go to hospital. Isn't 24 hrs too long, And he is trying constantly. Is there Anything to do to help at home. Is drinking limited fluids the longer he is unable to urinate. Thank You. Other health issues are stage 4 COPD due to mesothelioma