If Xorn was depowered, what kept his black hole brain from collapsing himself into it?

Final Arrow says:

"His mum"

I don't know much about him, what was the deal with that?

His mum

Xorn himself is a gigantic continuity error. Grant Morrison claims that Xorn never existed as far as he was concerned, but when he wrote his very first appearance it's mentioned numerous times how he has been locked up for more than half a century which isn't possible seeing as how--if he was Magneto--the attack on Genosha was only months before they found Xorn.
 
Xorn and his brother are just one gigantic mess, really.

@iLLituracy: Sadly...