I will start learning Java.

[Glome]

HTML is probably best to start out with, because it's like the backbone of internet languages.

Once you can make some basic HTML, you can start work on Javascript -- which is a bit easier than Java -- and PHP very easily.

Like on Buildism -- you have to build the car before you can script it to drive.

HTML, Javascript and PHP have nothing to do with Java.
Yes you can use them all to make a website with a game.

You shouldn't suggest that he learns HTML before he learns Java since Java has nothing to do with HTML (Except embedding an applet but that is different...).
However you should learn the basics of programming.
I suggest you check out some Java books those are usually the best way to learn.
But if you don't want to/don't have time you could look for some youtube tutorials.
I know that thenewboston makes some very good programming tutorials over Java.