this is 100% your companys fault. If this person is literally not producing anything useful, then set them a basic piece of work and tell them to complete it.

this is 100% your companys fault. If this person is literally not producing anything useful, then set them a basic piece of work and tell them to complete it. If they can't give them a warning, tell them to upskill. Repeat after a month. And again a month after that. If they still can't do it then you have plenty of evidence to justify firing them, anywhere in the world.