He burnt out his brain with brandy
Does "He burnt out his brain with brandy" mean:

1. He drank so much Brandy that he could not think any more.

or

2. He drank so much Brandy that he died of it.

Question

He burnt out his brain with brandy
Does "He burnt out his brain with brandy" mean:

1. He drank so much Brandy that he could not think any more.

or

2. He drank so much Brandy that he died of it.

Answer

He killed a lot of his brain cells and became terminally stupid. The usual way to say this is "The  alcohol fried his brain"

Answer

Most likely (1).

There are many people who are "brain dead", however their bodies continue to function normally.

Hence you may "burn out your brain", without killing your body.

The above sentence, however, is most likely an exaggeration, meant as a way of insulting a person; implying that they have become stupid after consuming too much alcohol.