I have an acquaintance who I have deeply upset because of my perspective on their past experience.

If a child (under 16) has an online adult friend (much, much older) who has severe depression and frequently speaks to them about their suicidal thoughts and mental health issues, is this morally okay?

If said adult makes it clear to the child that they have no other friends or family, and that their only reason to live was the child, what sort of effect might that have on the child?

If the child cannot mentally endure the responsibility of appeasing the adult and ends up blocking them, then never hears from them again, subsequently growing up and blaming themself for 'killing' said adult friend, what would you say to them? (For the record, there is no evidence implying if the adult has passed or is still alive)

Perhaps it's obvious, but when I suggested the adult was being inappropriate by relying too heavily on the child, my acquaintance replies with "age doesnt matter, we all mourn and feel depressed and they have a right to share it" and "if you cared about me then you would mourn too and not come across as judgemental when people go through their endeavours."

If it wasn't obvious, the child is now an adult.

What would you say to them in my position?

-----

Extra:

I know im the asshole. In the end I was unable to provide any comfort whatsoever. They had to leave because they needed to decompress and were evidently too disgusted with my opinion. I feel disgusted with myself. I dont blame them at all, since I should have just listened instead of inserting my god-awful opinion. I told them I was sorry and that their interpretation wasnt what id meant, but it didn't mean anything to them. It was too late.

They are mourning their friend that they deeply cared about and I shouldn't have commented on such a sensitive subject. I can't undo that. But it was heartbreaking watching them blame themselves, I just felt destroyed that an adult would do this to a child and that the intense guilt this was a consequence that my acquaintance shouldnt have to face. In my heart, I still believe that what they faced wasn't fair to weigh on a child, but after what they said about me being judgemental... I am questioning whether my logic has been clouded by my overprotective nature of this person. I really am ashamed with how I've handled this. 

It's too late to undo the damage I caused, and I doubt they will ever look at me the same way again, but I'm still wondering if i even had any right to say what I said, or if the general consensus is beyond me.

-------

Sorry for any typos or grammatical errors in this post, I wrote this while crying my eyes out. Now im about to cry myself to sleep haha... 

Thank you for any help you can give me.