Go check the profiles of the people who commented, and see if the account your questioning comments on their pictures too. It could be that they engage with their audience, so their audience engages back.
Comments bought or from an engagement group. likes seem a reasonable amount, maybe even a bit on the low side.
This guy is probably using comment and like groups, you can find a ton of them on telegram. They dont seem to have a lot of succes for this guy since he is only getting 500 likes (100-200 more than the amount of comments)
if the account has an bigger account behind it – the bigger account/s just needs to run it in it’s stories. It is insane how much traffic that will produce. They also could but story shouts. EG groups are possible as dm groups – personal friends to. There are many ways to drive traffic.