About the question...
The overall question is clearly stated and addressed towards the bottom of the post:
"How could I approach him with the topic again so he can understand my feelings and that he is not in a healthy relationship?"
This question is asking for interpersonal help (i.e. 'How do I communicate my feelings with another party'), has a clear goal, and has provided a lot of supplemental information about their situation (including what they have already tried). I actually don't really see a flaw with this question at all, given our site rules.
Most questions that get closed/'strictly moderated' tend to be questions that are open ended and are asking for general assistance without even defining a clear goal (i.e. 'Here's my problem, what should I do about it?'). The question you are concerned with in your post is not an offender of this, at all. OP has defined their problem, what they have tried, what their intentions/goals are, and what they can do going forward when addressing their friend - all makings of a good, on-topic question for IPS.
About the answer...
The answer, however, is a bit different than most standard answers we have here. It mostly fits into the description of a Frame Challenge, which you can find details for here: What is the difference between not answering a question and posting a frame challenge?.
The key with a frame challenge answer is that, if it isn't going to give the OP an answer to the question they were hoping for, it needs to provide sufficient information on why it is suggesting an alternative route. I, personally, would say that there is sufficient information in this answer to clarify why the writer is suggesting the OP do something different. Because of this, I would encourage downvoting it if you disagree with it.