Urine disorder for pill overdose?

I've looked everywhere and have come here for help. A few years back, my boyfriend was going through some tough times and had overdosed on 30+ pills (advil, tylenol, ect..). He had gotten help and is now in a stable point in his life, except there's one very serious problem. Since the overdose, he has had trouble when he urinates. After he urinates there is continuous dripping (after he urinates it does not all come out). He has to stay in the bathroom for long periods of time to make sure it wont drip on his clothing. Even after spending quite some time in the bathroom, he still has some dripping problems. This interferes with many of his daily routines, such as driving and simple things as watching t.v. We were hoping to get some insight as to what this could be and possible treatments. He's discussed this with several doctors and they pretty much said there was nothing he could do or that it wasnt unusual. Hopefully this isnt the case. We appreciate any help. Thanks!