Does "broken up about" mean "cut off the relationship with"?

No. It doesn't mean that. In theory, it means he's emotionally devastated. With the use of the term 'dead hookers', I suspect it could be a sarcastic remark claiming that Phil is emotionally devastated about the deaths of the prostitutes he either uses regularly or under his hire (as in he is or was a pimp).

Either way, "broken up about" is an idiom about being emotionally wrecked about some personal event.

No.

Idioms again.

http://www.english-slang.com/eng/american/i_b/848-break-up

(category - American idioms)

I cannot open it.
It seems our insane government has blocked the site.

Do any of the sites that cover idioms work for you?

It is helpful for us to know if you can't access the sites that review/discuss English-language idioms as it explains, in part, why you're having such difficulty with them.

I'm not sure how you're supposed to do your work if you're not allowed to access resources that would increase your ability to do that work effectively.

There are many jokes in North America about the odd descriptions of things coming from your country. I'm surprised the government doesn't put more effort into letting people learn English as it is actually used.

What a minefield you have to deal with, with idioms I mean. And American idioms are often different from UK ones.

"broken up with" means separated from.
"broken up about" means upset about

The first of these is common in the UK, the second is almost exclusively American.