What's causing Mom's urination hesitation?
You will have to develop extreme patience with this stage of your mother-in-law's care. If it is not medical, you may never know what is causing the conditon of urination hesitation.
Something is clenching up!
How can you help you mother-in-law relax so that she won't feel embarassed if she has an accident and so her urine can flow. She holds on and later lets go. What is causing her to tighten up.
It might be something simple. Where is the commode? Is it private? When she sits on it what does she look at? Can she see out the window or look at a picture that is pleasing? Or what about touch? Is there something to hold while she sits on the cammode:a soft cloth or a soft little stuffed animal or a smoothe stone. Some people relax more when they are surrounded by favorite colors. You could try colored light bulbs or hand towels or wrapping her in a colored shawl. If her hearing is good, music might be nice or one of those little fountains that give the sound of flowing water.
Also, she might be clenched up by fear of her condition. You might talk with her. Acknowledge her illness, but assure her that she can still have some enjoyments? What would it be for her? Can someone in the family take her for a drive? Could someone take her out for an appointment; then stop at a drive-in for a hot fudge sundae? Think of some activity that might be relaxing for her---and for you.
Try to get the support you need to stay patient. Though temporary, this is a very difficult period in the tender care you are giving to your husband's mother.