From what has been said, in principle, it does not appear that he has broken any rules, although it does not seem to me ethically correct to use the forum only to gain merit and not to exchange opinions in a constructive way, and that way of writing that looks like a bot makes me think that there is something wrong with that account.
I'd advise that you just put him on close watch. Like you said, he hasn't broken any rules of the forum (yet) and if he is an old user in this place like you said, I'm sure he must know about the dos and don'ts so although it's not cool to participate here just for what you'd gain, in terms of the merits and all that, it's still isn't a crime, right?Even if it seems like he's just sucking up to the big guys just to get the merits, it's not enough to call him out until he does something really iffy..