Using a Bedpan
If he is totally confined to bed, then it is necessary to use the bedpan. For a man, a handheld urinal would be adequate for him to pass urine. Note that he may be reluctant to ask for one, so ask him frequently whether he needs one. Always give him complete privacy and plenty of time.
To use the bedpan, start by propping him up in bed. Then, sprinkle powder on the rim of the bedpan to make it easier to slip it under the buttocks. Then roll him over to one side, put the bedpan on the mattress at the level of his buttocks and push it down as you roll him back. Help him to adjust the position of the bedpan until he is comfortable.
Again, give him plenty of time.