We can't know if the story is true, sure. But I have no reason not to believe him as long as I don't make any important decisions due to that fact.
If his computer is compromised, everything is lost, of course! But the reason I'm asking is, if he maybe changed his password just yesterday, this could indicate another attack vector (keylogger) than maybe a break-in to his email account or a breach in Havelock itself.
Physical theft is an option, yeah. So: How many people do know you're "into Bitcoin" or own AM shares? Do they even know what AM shares are? Did you tell people about it?
There are lots of pathological liars in this world who can be amazingly convincing.
Physical theft is a very real option. Many people tell their friends, spouse or love ones about their investments. Very few people can keep it a secret.
You'd be amazed how often the person responsible is a room mate or someone close.
In this described event of getting access to 2 factor I think these 2 scenarios are highly probable.
I think a Havelock "rogue" trader would have targeted an even bigger account or several such accounts so I don't think that's the case.