92 Year Old Father / Very Active For Age .

92 year old father / very active for age . Alert and still drives . 10 days ago flew to Florida with his wife to their home for the winter . Last 4 days has experienced waking up at night in a sweat and dizzy and on first getting up in the am is dizzy. 4 days ago Went to ER EKG, vital signs normal , blood sugar in the night was 140. My mother notices he has periods he stops breathing briefly during sleep at night . CT Skan negative. Hx : Underwent left knee replacement in November 2016 in Chicago. Had an epidural for the surgery. First 24 hours after the surgery had delay in Right side of body returning feeling and strength . Did very well post op.
Went to ER and sent home 4 days ago. Back to walkin clinic today and resent to ER. vital signs and pulse of are normal. Labs show some dehydration ?