You don't need to have someone write code to find out if they know how to code, or how well. Simply ask a series of increasingly deeper questions about a range of coding topics that elucidate both technical expertise and experience. If you don't know all of that yourself, find someone else that does and have them do the interview. I've always been able to conduct interviews and find out someone's strengths and weaknesses without seeing them write code or fix a broken thing. Maybe I'm just some magical unicorn and this is a super rare skill? But I doubt it. I'm just looking for the tell-tale signs of someone who has done real work and learned things in that process.
The other thing is, as someone hiring, my main concern is just making sure the candidate has the specific skillset or experience I need. The person may learn quickly, but I probably don't have time for them to learn the one technology I need them to use ASAP. A lot of candidates end up getting rejected because they put something on their resume that we really need but they don't know well enough. And some just seem to be trying to reach and do a job they don't have experience in. It's hard to find someone who has just done the job I need done and isn't trying to get some other job.
The other thing is, as someone hiring, my main concern is just making sure the candidate has the specific skillset or experience I need. The person may learn quickly, but I probably don't have time for them to learn the one technology I need them to use ASAP. A lot of candidates end up getting rejected because they put something on their resume that we really need but they don't know well enough. And some just seem to be trying to reach and do a job they don't have experience in. It's hard to find someone who has just done the job I need done and isn't trying to get some other job.