My Dad Is 89 And Has Had 3 Or 4

My dad is 89 and has had 3 or 4 episodes in the past week or so of waking up extremely hot but no temperature...chills somewhat...tightness in his legs and hands ... I have assumed it was anxiety just being fearful...he has had a GI bleed about 2 months ago but is not complaining of pain.. He lives alone but is with me now. He says he is shaking inside...he is clammy.... ?? NO pain just shaking he says he doesn't know how to explain ..shortness of breath...like he is tight from his feet to his hands... (scared) ..