Perhaps LLMs can be used to gain some working vocabulary in a subject you aren’t familiar with. I’d say anything more than that is a gamble, since there’s no guarantee that hallucinations have not taken place. Remember, that to spot incorrect info, you need to already be well acquainted with the matter at hand, which is at the polar opposite of just starting to learn the basics.
I’d put my money on that account being hacked/sold and gaining a new life as a bot in some disinformation network ready to spew bias and bullshit when the time and topic is right. There’s no other way to explain the comment history before 9 months ago, then a long silence, and then a restart just a few weeks ago with a complete change in character.