One person attacks two bases in a clan war, destroys them both 100% (3 stars X 2 =6 stars) he can only get 3 stars for the clan will the second base show his attack at 100% (3 stars) if so how do we know that it is still available to collect 3 stars for another member to attack and collect for the clan score?
Unless there's been a recent update to change this a player can get 6 stars for his clan from war attacks assuming he 100%'s both bases and neither had already been hit, meaning any other attack will just be for war win bonus
A player can attack 2 times. A base can get attacked an unlimited amount of times, but only 1 time by the same player. Only the best attack on a base will count the stars for the clan total, otherwise everyone would just attack the 2 bottom bases and be done with it.
So if I get 2x 2 stars, the clan total will be 4. If you then attack the same two bases, and get 3 stars on each of them, the clan total will be 6.
Basically, count all the stars above the bases of the enemy war map, and you get your clan total.
It is no problem for a player to earn 6 stars for the clan total, his second attack will totally count.
I hope my answer was clear, because your question wasn't really. You might want to try rephrasing your question if this wasn't the answer you were looking for.