My father is suffering from chicken pox...he's 40 years old...as a child he had suffered a very mild chicken pox attack. could someone please advice me.

The question is ???: People seldom went in for medical evaluation 35 yrs ago when they thought the problem was something simple like chickenpox. It was easy to over diagnose when only a few spots were present. People do get it for the first time as adults & it can be quite harsh. Many have significant disability & a mild encephalitis while rarely a pneumonia can require intensive care. Most recover without problems.