Terminal illness is a disease that cannot be cured or adequately treated and that is reasonably expected to result in the death of the patient within a short period of time.he six-month standard is arbitrary, and best available estimates of longevity may be incorrect. Consequently, though a given patient may properly be considered terminal, this is not a guarantee that the patient will die within six months.
1 Stop metformin if the eGFR is below 30 ml/minute/1.73m2.  Prescribe metformin with caution for those at risk of a sudden deterioration in kidney function and those at risk of eGFR falling below 45ml/minute/1.73m2.
Metformin can cause vitamin B12 deficiency in some people and this would decrease blood counts leading to fatigue (and generally difficulty with problem solving, periperal neuropathy, etc...) so the lab work would help identify cause.