On the other side I think that he unfortunately has every right to post 10times a day and as long as rewards are not outrageous, should we intervene?

Of course, that is his right. It's tricky to say how much he should be earning, but that's open for the "collective negotiation", if you will, via downvotes/upvotes according to people's conscience – that's how proof-of-brain is supposed to work.

Best luck to you and here is a small upvote from me

Thanks, it's appreciated :)