I'm NOT a physician but I have seen a number of patients, both ambulatory and confined to bed, who have indwelling catheters inserted into their urethras so that urine can drain out as necessary to either a convenient bag, bottle or other container depending on whether or not the patient is moving around.  The catheters can be replaced periodically to minimize likelihood of infections arising. They are usually not painful unless there is an underlying infection irritating the urethral lining, they are too large or they are roughly inserted.  You might consider this as there is no need to use diapers if properly inserted, and the patient does not have to get up during the night, hence sleep should be improved.  If the patient has latex sensitivity, then you should avoid the rubber type of catheter.  Of course, you should ask your physician if this is a prudent course of action to relieve your father's discomfort or need to urinate frequently.