i would suggest getting him evaluated by his physician sooner rather than later. there are several different things that can cause this type of sudden behavior change but diagnosis will probably require a test or two. good luck!
what would cause a 61 yr old male to all of a sudden be terrified to be alone? . is for some reason terrified to be alone. he often outa the blue starts crying. when asked y he says he don't know. he doesn't have any physical pain. he don't have any viral or bacterial. sickness. or symptoms. he does have bad anxiety. loss of appitite and sleeps almost constantly. he has become really needy im guessing anxiety and depression. but why or how just like that causing such dramatic change in behavior in a matter of a few days?