Get that interview process fixed ASAP and let this lemon go. Don’t be surprised if there is pushback from non-technicals if this hire checked a bunch of boxes for other departments.
A good strategy would be to have them be a lead on a minor project that requires technical chops and communication. Ensure there is a daily standup and grind them on details and timelines. Get them some juniors as direct reports to expose their lack of knowledge, then have meetings with these junior devs about project performance.
The stress alone will probably make them quit. Document as much as you can in emails and messaging systems.
A good strategy would be to have them be a lead on a minor project that requires technical chops and communication. Ensure there is a daily standup and grind them on details and timelines. Get them some juniors as direct reports to expose their lack of knowledge, then have meetings with these junior devs about project performance.
The stress alone will probably make them quit. Document as much as you can in emails and messaging systems.