High or low sodium and potassium levels

Patient: My 78 year old father has had a weight loss of 30lbs over the last 2 months. He’s had CT Scans and MRI’s recently to check some abnormal growths on his spine but after 2 years of following these there has been no change in them. He began losing by cutting down on the amount he eats, he says now he doesn’t really watch how much he eats but he continues to lose. He denies excessive thirst, his Dr recently did blood tests and he was told everything, including Cholesterol, HDL, LDL, were all within normal range, but told him to start drinking 1 gallon of water per day. I have to assume it was his electrolytes that were the Dr’s concern, my father can’t remember why, could it be his sodium and potassium were slightly elevated or would it be that sodium and potassium levels were a bit low?