No, they should not continue to be in a position where they can continue committing grossly negligent actions and harm others.

You can train them once they are removed and reinstate them when they can do the job right, but supporting their continued harm of others so they can “support themselves” is detrimental, counterproductive, misguided, and extremely selfish.

You are literally better off paying them to do nothing. Please at least do that instead of paying for harm.