My Mom takes care of the 90 year old grandmother. She has noticed lately that my gram will go into the bathroom and spend up to an hour or more sitting on the toilet. When she asked my Gram if she is done she will say no. She sits there and counts the flowers on the wall paper and tiles on the floor.... She even closes her eyes, like she is sleeping. Mom sits close by to make sure she does not fall off the toilet. She is concerned, what can she do? My gram is still
independent and does appricate someone telling her it is time to get up....
However, it is rarely available because my husband is using his chromebook in there! I say, keep moving, your legs can go to sleep and you cannot get up!
All the above are good suggestions but wolflover has made the one comment I would endorse as being the most important. This is very true for the heavy elderly. If they sit too long they compress the nerves in the legs and they don't just go to sleep they are temporally paralysed. Raising the feet on a stool both helps elimination and prevents nerve compression. Hemorriods are about as likely as sitting on a cold stone step which is what my grandmother used to tell me. Well I have them anyway but don't think the cold step was the cause
Then look at the diet. Does it encourage daily comfortable bowel movements? Make that your goal. Keep adjusting the diet and water until you get it right. Use a pressure cooker to keep a supply of beans and cooked fresh greens on hand. Once you cook a big batch it can be frozen in smaller batches. Then thaw as needed. Are they getting 5 fruits and 5 vegetables every day? If not adjust these first to meet the goal. One daily serving of grapefruit is an automatic: comfy, speedy, well formed and thorough "bm" at our house. But grapefruit is not compatible with all meds. Whole fruit and vegetable smoothies also help you to meet the 5&5 qouta. I'm always amazed at how beets taste like strawberies in a smoothie. Prunes have a multi century reputation for enhancing regularity ... for a reason. LOL.
If your loved one still wants to sit for more than 15 minutes, what else can you do. Provide a cushion/padded toilet seat. Verify that they are not pushing or straining. Inspect bottoms, undies and bedding for signs of blood or seepage. Use an anti diaper rash/ pressure sore med like Aquaphor Healing Ointment Advanced Therapy one a week as a preventative - this stuff is amazing. See if they just need a change of view. Have they been cooped up in the same 4 square feet all day every day? can they get some sitting time or activities out side. Exercise also stimulates the bowels. Sweep the sidewalk, weed the garden. walk the property. Walk the mall. Walk the farmers market. walk a museum. Do chair exercises. Dance. It's all good. :).
Hospitals use MiraLax or its equivilant, daily and over a long period of time. If you tolerate those kinds of things well, it's something to consider. Ground flax seeds and other fiber enhancers help some.
Finally encourage them to use their own hands to deep massage their own upper thighs and buttocks. They can be rougher with themselves than you can be. It's good for the hands and whatever they're messaging too.
My loved ones have napped and read newspapers on the john for decades with no ill effects. Now they're octogenarians, they say that they just like it in there. If there are no ill effects or inconvience ... decide to worry about something else.
I hope this helps.