"Kim Jong-nam, half-brother of North Korean leader, 'was a CIA informant'"

From the link in the OP:

Kim [Jong-nam], who was once considered the favourite to succeed his father, Kim Jong-il, as leader but fell out of favour, was probably unable to shed much light on the regime’s internal politics.

“Several former US officials said the half brother, who had lived outside of North Korea for many years and had no known power base in Pyongyang, was unlikely to be able to provide details of the secretive country’s inner workings,” it said.

The post that was quoted here has been removed

I think it's fair to say he'd have been a person of interest to many of the world's intelligence agencies. But his informational value would be more along the lines of what the personalities involved are like, what internal frictions there were before he fled, background information basically. All he could hand over as actual information would be early details about the existence of the North Korean nuclear weapons program. He might act as a consultant expert on what information the CIA has from signals sources means.

I'm wary of the notion that the purpose of his travel was to meet a CIA handler. They'll have had a simpler method of getting in touch, that didn't involve international travel.

Kim Jong-Un's motive in ordering his killing is, I think, no more complicated than demonstrating that he is prepared to assassinate or execute family members for slight signs of disloyalty. Anyone not related had better watch out.

The post that was quoted here has been removed

I think we more or less agree. Just a point though, he wouldn't necessarily know that the person he was talking to was an intelligence officer. He might think he was just chatting with a business person. They don't necessarily have to formally recruit him. Given that he wasn't given sanctuary it seems possible that contacts with Western intelligence operations may have been unwitting.