My mother has severe urine incontinence and occasional fecal incontinence. She wears depends, but inevitably soaks her clothing and sheets several times a week. The odor is horrible and even with repeated washings - vinegar, baking soda, odo-ban, detergent, fabric softener - the odors remain in some clothing. I do know that hot water helps, but everything can't be washed in hot water. Also, she has very sensitive skin and I have to use free & clear detergents. Borax is going to be my next try, but I would appreciate any suggestions.
Lastly, place the items in direct sunlight for a few hours - this will often remove stubborn odors. You might also try doing some research on pet urine removal products. I believe these are a combination of natural items which you can even make at home in large batches.
www.agingcare.com/questions/remove-urine-smell-sheets-clothing-163526.htm
Buy some underpads (Chux) for the bed and those can be washed saving the sheets