mysql – Apache server and database

So, I have created a website for my friend and I am about to load it to my friend’s server but He already has a FIVEM GTA server running on it, thus I am afraid that through my website someone can destroy the whole server, or at least the database. I have already included prepared statements to protect from SQL injections but I have no clue what security measures to do other than SQL injection protection.
Can I get some advice or tips how to do this properly without taking any risk in destroying the server that my friend has been working on for months.
I might be wrong but making a new connection in the database is necessary.
Any help would be kindly appreciated, and sorry if this is not the right place to ask this.