Cholesterol medications are very hard on the liver, so this could account for the elevated liver enzymes.
But left sided pain could be pancreatitis. If you can get her to take juniper berries these will strengthen the pancreas and help with the water retention. They also aid with digestion. But they also do a great job lowering blood sugar so this herb is best taken with a little food.
The IBS and bloating indicate a lack of intestinal flora, so fibers and kefir. Make sure they are soft fibers like rice bran so the fiber will help heal and not aggravate the diverticulitis.
The weak nails and diverticulitis can indicate a silica deficiency. If she will not do the DE then the rice bran will provide silica. Nettle leaf and chickweed are also great choices. A little yucca root will help clean out the diverticuli and reduce the inflammation, while helping build up the flora and adrenals.
Lulu, what a nice letter. Your Mum sounds wonderful and she's is very lucky to have you.
What it sounds like you want is a "prescription" you can show her from a "Dr. Hv" because she's of the generation that follows doctors orders like all good people did.
Once you find out what would help her maybe if you write it out for her and get one of those days of the week pill boxes (some have 3x a day) and fill it for her she'll follow doctors orders more than your suggestions.
Another thing that may help is relaxation music or CDs like MammacatPatch suggested called the Delta Sleep System.