"He finishes writing the article."
Translation:Он заканчивает писать статью.
No, because if he is finishing doing something now then by definition the action is not yet finished, i.e. we can't use a perfective verb here.
I was curious about this too. Isn't there a way to say, "He wrote the article."?
That would be "Он написал статью". but "He wrote the article." is different from "He finishes writing the article." both in English and in Russian.
We don't say оканчивает in such sense. You may use оканчивает for translate he is finishing the university/education/course - он оканчивает университет/образование/курс but not он оканчивает писать/читать however people will understand you.
Заканчивать you can use in both cases and this word is more common
It looks like you didn't use the correct Russian letter 'yu' at the end of the phrase. You have written 'IO' instead.
No, there's no such word as "скончит" in Russian. There are "закончит" and "окончит" (both mean pretty much the same with the former being more common), but they are in the future tense - "he will finish".