Earlier quoted context omitted.
You don't have to agree with me, and that is OK. But my opinion is based off of experience. You might be interested in http://www.govtilr.org/Skills/ILRscale5.htm as an example of the scales used when defining levels of competency.
I'm sure you meant this reply to be constructive, but without describing the experience in question or saying which category from your link you think applies here, it doesn't convey anything. For me, my experience is two years as an English teacher and my opinion based on that experience is that someone who can convey complex ideas clearly and without effort is fluent. If you define that to be intermediate, what's le…
http://www.govtilr.org/Skills/ILRscale2.htm
Based on the criteria given, I would estimate that his English writing ability is ~2+. Without hearing him speak, I can't properly assess. Perhaps a 3.
None of this is a criticism or a put down. Achieving this degree of competency in a second or third language takes a great deal of work over a long time, and is something to be proud of. But true fluency happens at level 4 and above.
(My father was a professional linguist and diplomat, and I spent much of my pre-adult life living in different non-English-speaking countries. I say this just so you know where I am coming from. I also want to spread awareness of what the various professional standards of fluency are.)