Is there any indication his email was recently changed? If the email was not changed, the account presumably was not hacked -- this is speaking nearly four months after any potential hack. In general, hacked accounts will immidiately try to scam or otherwise cause damage because of the ongoing risk that someone will come along claiming to be the original owner of the account. If the email was not changed four months after the fact, there is also the risk the owner will simply reset the password via email to reclaim the account.

I am not aware of any hacked account causing damage 3+ months after the fact.

I would also not be especially surprised to see someone reseting their password via email after a long time of inactivity if the password was semi-unique, as people tend to forget these types of things if they have not used them in a long time.

The loan request was clearly not a serious request, and was more along the lines of pointing out all the ridiculousness in the lending section.

To be entirely fair, this is a question that you asked, and according to you, it was answered correctly. As you point out, the reference is only available to a small set of people, so someone looking through his post history would effectively need to do so while logged into his account.

I don't think there are many people from 2011 that can sign pre-2014 coins, especially large in large amounts. I suspect that most who did not cash out in 2013, cashed out in 2017 when the price went up to $20k. There are also probably a decent amount of sad sacks that cashed out at $20 or $50. Others probably did not put a lot of effort into ensuring their private keys worth $500 would remain when a HDD is no longer available.

I think the account is most likely not hacked in large part because he hasn't tried to cause any damage in the four months since he returned, despite having a very low profile. There was this thread, but it did not get much attention.

With that being said, he has very little trade history to start with, and as I pointed out here, it is usually not a good idea to trust someone (with a long/successful history of trading) after returning from a hiatus as their situation may have changed and caused them to be willing to do unsavory acts.