Adult diapers are leaking. Is this normal? What can I do?

My grandmother, who lives with me, wears maximum protection/absorption adult diapers 24/7. But at least once a week, she wets the bed to the point of having to change the sheets and her clothes (I do use a plastic bed protector). She never mentions the bedwetting. She just changes out of the wet clothes when she wakes up and puts them in the hamper. Sometimes she can go 10-14 days without an incident, but this week she's wet the bed about four days in a row.

I'm trying to schedule her a doctor's appointment, but some of the doctors (gynecologist and urologist) I called either don't take Medicare (!?) or don't deal with her specific issues (she has a pessary). Plus, she's had other issues that needed to be dealt with first (possible cancer).

Anyway... the point of my post is that I don't understand why these "diapers" are leaking. They have good reviews and seem absorbent. She doesn't drink that much a day. I'd say she drinks a minimum of 20 oz. to maybe 28 oz. per day. Some of her food has liquid like milk in her cereal or the canned fruit she eats. She eats about one 14.5 oz. can of mixed fruit per day. She usually doesn't drink within three hours of bedtime other than the sip of water for her pill. She does usually have a small snack between 9:30 pm to 10 pm with bedtime being between 11:00 to 11:30 pm. So it would seem that these "diapers" shouldn't be leaking. I'm sure she's pulling them up far enough and I've even tried a different size on her.

I guess I could try a different brand, but most I've seen are considerably more expensive. She's wearing Walmart's brand now which costs about $22 for 60 diapers.

Any thoughts or suggestions?

And if anyone has any tips for removing urine smell from clothes, please share it with me. I was using a pet enzyme cleaner which works, but I don't like the smell. So now I'm using distilled vinegar. First I rinse the clothes with cold water, then I let them sit in a water and vinegar mix for at least an hour. Then I rinse them, and if they smell ok, I then wash as normal. I just don't like using vinegar as I'm slightly allergic to it.