Here every doctor has studied 5 and half years on human bodies (allopathy) and alas u r so much worried abt ur parrot. 2ndly u should show him to a person who is expert in veterinary sciences I think he has developed ocular myasthenia and has developed ptosis which also happens in humans check by a fundoscope if he has associated pupil involvement. Can start him on steroids or pyridostigmine.if u wish I can suggest the dose Also a nerve conduction test wil help 2ndly u are worried if he is feeling low..whole humanity is feeling low sir..people are dying lockdown everywhr and yash tornado has hit westbengal think of the people who are feeling low in that.Atleast ur parrot can fly..let him fly little bit..bt tel him to use mask. However I can also suggest lithium which wil elevate his mood or benzodiazepine so that his depression goes away or u can show him to a psychiatrist. Thanks