Student visa rejected but applied for Visitor visa

My fiancees brother applied for a visitor visa to come to our wedding but he has just received a rejection saying his short-term student visa has been rejected. I have his application and it clearly shows he applied for a visitor visa, not student. The rejection also says that he applied to study English language at Kaplan. He did not and there is nothing about that on his application, I checked and Kaplan don't even have any English courses.

So to me it seems very strange, it's as if his application has been mixed up with someone else's, is that even possible?
Any advice?
I've tried phoning UKVI/Home Office, they were completely useless so I have now paid £5.46 to send an email to them.

There are different types of visitor visa. Whoever filled the application might accidentally chose wrong type. I am not sure if in the application itself it will distinguish between types of visitor visas. But Kaplan... Strange. If this is not the case, wait for a reply from HO.

Best thing to do is to re-apply and in your covering letter, address the rejection about what UKVI said about study and include all that you need to do for his visit.

Very bizarre, but UKVI are known for a mix up of rejection letters and indeed, sending passports to the wrong people.