Friend is 'unclickable' on friend list?

[History Nut]

I was scrolling through my friends list and one of my friends has their name in black/grey and you cannot click it at all. They haven't deactivated as some of my other friends who have deactivated are still in blue and when I click on them it gives me the option to fully remove them.

The person in grey/black is totally unclickable. They wouldn't have deleted me but I can't get in contact another way because he lives in a different country. Any help?
It gives me the option to unfriend them too. I can't see them when I search for them or click on their profile at all!

[Daniel]

That Means They Have Deactivated There Account Deactivated Accounts Stay in your Friends List Until you Remove them From your Friends List

[Fáyíz]

Most probably Facebook have DISABLED their account for some reasons.
When this happens ,the person's name blackenes out with link made un-clickable and Pro Pic Gone.(Will be the default fb pro pic with sort of white/blue combination)