Hello Kessia,
There are usually three main causes of kidney failure and one of them can be dehydration, not enough fluid in the can harm the kidneys.
Since your mother had serious and long-term health problems it is big possibility that her kidney problem is caused by medicines but off course you need to talk to the doctor’s about the cause of renal failure.
Some of the medicines which can cause kidney problems are antibiotics such as gentamicin and streptomycin, pain medicines such as aspirin and ibuprofen and some blood pressure medicines such as ACE inhibitors.
When treatment options are in question usually treatment is focused on the cause of the kidney failure.
For example if the cause of the kidney failure are medications which your mother is using, you will need to stop them.