Disclaimer: This is for 1.8.9 but this wont let me select it, sorry for the inconvenience

So I created a LAN world where I made of bunch of command block creations (In a map I downloaded) to make the survival vanilla part more interesting, I am using a good Desktop, my friend is using a laptop.

At first my friend would lag a bit but it would be fine if he wasn't to close to the command blocks and spawn town, but now whenever he joins he gets kicked shortly after with a random message, usually one of these:

-Badly compressed packet (Random Number) is smaller than something 264
or
-Unexpected header

sorry they aren't exact, I can't remember exactly what it said...

But anyways it's really annoying because we can't play and I spent so much time on creating it and he can't stay on for a minute without being kicked, whenever we try to find a fix people say something about max-bulk-chunks but they don't say how to change it OR they say it's a problem with the plugins, and we're using vanilla clients. Are the command blocks too much for the laptop? If so why would it give such a weird message, please help it's very annoying and I've spent too much time trying to fix it.