Hello!
Your father seems to be suffering from an anxiety disorder which is very common and looks like its been triggered by the sore throat episode and fear of having corona. Usually, anxiety disorders first need proper evaluation, and the best and safe medicines to treat it are SSRIs , which can be taken for long period , alprax is a benzodiazepine that are habit forming medications and cause dependence and cognitive issues at this age like forgetfulness if taken for longtime.
Next Steps
You better consult a psychiatrist and get your father fully evaluated.
Health Tips
Never try to self medicate yourself or your dear ones with drugs like benzodiazepines.