My brother is talking to him self all day long none stop.?

Wait till you find out your brother is an only child and you're just a figment of his imagination... 

Hopefully, it's just a case of "the DTs" and it will go away in a few days. If not, this is something that calls for medical care. Psychosis responds to medication. The good thing is he's not drinking and you can be grateful for that. If he wants support, there's AA of course, also SMARTRecovery.org, which is ex-addicts who believe in psychology. They have a program based on the standard counseling methods.

If he never drinks again, chances are good.  What you are seeing is the withdrawal from alcohol with maybe some other mental issues that your brother has been "self medicating" himself to avoid.  Once the physical withdrawal issues subside (the shaking is a classic symptom) the other mental issues can be addressed and that will take some time and whole lot of difficult effort from your brother.

Is this sort of thing normal?  Yes, but only in the most extreme cases of alcoholism.

Robert Trump, is that YOU calling from the grave??

First of all are you sur he’s talking to himself and he’s not playing with people who are talking with him on discord / psn chat / xbox chat ?

If he’s playing with other people it’s pretty common to talk to people because one it’s faster than typing and two well it’s more social. When I play in raid I laugh with my team because we are having fun.

In some cases I talk alone too and depending on the game it helps me planify my strategy for some games (city builders, 4X this kind of games) it’s a reflex I have from my job where talking to yourself loud could help to find solutions which you are not thinking right away.

If you think your brother has issues I invite you to talk with him and if it’s the case to ask for the help of a professional

It lasts a few days. Look up 'Delirium Tremens' online. That will tell you all about it.