1-means he always watches t.v
2-this sentence must be followed by another sentence to be meaningful.otherwise, it is not possible ( for me) to decide which one to use.
3-IS is better when for example, at night father comes home, and mother wants to complain about his son, about that he hadn't studied his lessons. she says:
He is always watching t.v when he comes home.
this means that after coming home from school, he doesn't study enough, and watches t.v programms more than enough.
4-WAS is used when for example a child brings his report card home with awful marks, and mother says the father:
He was always watching t.v during his exam.
this means that in the period of time he had exam, he had watched t.v more than enough.
5-I am fond of reading means that right now, i love reading a lot od books.
6-I was fond of reading means in the past times, i was interested inreading, and i read a lot of books.
7-I have/had always... means in past, but before s.th happens, i used to read books. s.th special happened and after that, i didn't read books anymore.
Hope that helps
Student or Learner