The co-worker who merely fails to do his or her job has been the least of my head-aches in the various teams I've been on. The co-workers who are competent enough to be influential but incompetent enough to insist on poor design and process decisions are the one who have done the most damage to projects I've been on.
That said, you really should verify that he is the one who is incompetent. Pointing the finger at others has also been a clue that a given person isn't really a good person for a team.
The point about finding something he can do seems good. If someone knows they aren't good at difficult problems, it can work well since you can give them "grunt work" and they might be useful.
But really, the most damaging thing isn't someone's degree of incompetence but their exaggerated idea of their competence. If other people helping him is the worst effect this person has, he is low on my scale of damaging co-workers.
That said, you really should verify that he is the one who is incompetent. Pointing the finger at others has also been a clue that a given person isn't really a good person for a team.
The point about finding something he can do seems good. If someone knows they aren't good at difficult problems, it can work well since you can give them "grunt work" and they might be useful.
But really, the most damaging thing isn't someone's degree of incompetence but their exaggerated idea of their competence. If other people helping him is the worst effect this person has, he is low on my scale of damaging co-workers.