Hello, My Father-In-Law Is 80 And Is Very Weak, Lost

Hello,
My Father-In-Law is 80 and is very weak, lost weight and is trying to quit smoking. About 3-5 months ago he started feeling cold and chills every day after 7 PM. He is feeling chills in a warm room even though he has normal body temperature. His hands and feet are cold. After about 2 or 3 hours he goes to bed he gets warm and in the morning he is fine. He walks a little bit, but feels no strength in his feet mainly below his knees. So why does he feel cold in the evenings?

Thank you