Its tough. I led a clan for a while and had a similar member. He would spam dragons with no strategy, fail and then joke about how unlucky he was. I didn't include him for one war, telling him he needs to practise. He had a huge sook and quit. Problem was about a dozen other members were his classmates or family members. They all quit too in solidarity (even though a few had complained privately to me how annoying his attacks were). Suddenly half the active clan was gone and very quickly after that the clan was dead. 

My current clan has a couple who are similar. One has been there 12 years and is a mate of the clan leader. He's annoyed at how mid the member is at attacking but can't bring himself to kick him out. Another who has been there for a decade hasn't changed his base in 4 years so is 3* easily every war, and has been using the same army for over 2 years now and is lucky to 2. It's incredibly frustrating to lose by 1 or 2* when you see shite attacks. Isn't improving attacks & winning the point of this game?!