Hello, I can understand your concern for your daughter in law and i appreciate it fully. I want to tell you that potassium is a very critical electrolyte in our body and it must be maintained in normal range. Anything outside the normal range (3.5 -5.1), whether increase or decrease, will lead to serious consequences. In your case, low potassium level can lead to muscular weakness, fatigue, muscle cramps, hypotension, palpitation, cardiac arrhythmias or even cardiac arrest, if the level is critically low. First of all, you need to supplement adequate potassium orally or intravenous. You can give orange/pineapple juice, coconut water, to your daughter in law, which contains good amount of potassium. I would like to suggest you to find out the cause of hypokalemia. There are many possibilities like renal loss of potassium in case of acute tubular necrosis, use of diuretics for congestive cardiac failure, in case of correction of diabetic ketoacidosis by insulin and glucose, intestinal loss through diarrhea/vomitting, during alkalosis, etc. So find out the cause with the help of your physician and treat accordingly. Hope this answers your question and feel free to ask any of your further related queries.