A friend of mine is playing with me on version 1.15.2 on a server
but recently he has had a 5 minute Disconects.
Can someone help me?
This can have many causes, e.g. Bad internet connection (overloaded due to Corona), insufficient memory, wrong / old JAVA version, etc. If this happens on a foreign server it can also be due to the server. The range is almost endless. There's no one-size-fits-all solution.