Problem with uploading website

Ok guys I have been struggling with a problem. The server helpdesk is being annoying and the other web developer is unreachable so I come here to ask if anyone knows an easy fix without fucking up the things. Problem is this. I made a website ( lets call it website A) and want to put it online, we already have a server with a website on ( website B) made by another person. So in the directory in the public_Html there are a couple of files, file for website A and file for website B, Website B is a wordpress site, and for some reason the developer didn’t put it in the file B it put it in the public_Hmtl, and inside the public_Html is a PHP file, saying, on loading this file, load the wordpress header, meaning, whenever I try to load website A it gives an error 500 because I geuss, it just totally gets ignored due to the PHP file. How can I solve this with minimal touching around website B as I really dont want to fuck up anything. Anyone has any ideas?

Thank you!

You can not have multiple index files inside your public folder. Try moving all the php files inside a subfolder so it can not be accessed through public directory and instead your site loads up.

But wont te site of the wordpress PhP Fail then? I’m pretty scared to fuck that up.