The buyers agent commission means the buyer agent splits their commission with the buyer as an incentive to work with them. Agent fees are negotiable but it is honestly only done by agents who need more clients as essentially a promotional thing to build their client list. Any established agent will politely say "Thank you for the opportunity to do business but I have a minimum commission which does not include a rebate. If you would like to work without the rebate please let me know"

Essentially if the buyers agent commission is 2% paid by the seller on a 300k house, then the buyers agent gets 6k and they could offer to only take 1.5% and rebate 0.5% back to the buyer giving the buyer $1,500 before taking home $4,500 (minus brokerage agreements)

End of the day this guy is saying "I've done all the searching work so give me a discount" but my agent willing to work with him will probably say "sign a 6 month contract with me to be your exclusive agent. You will get 0.5% back on this property only and I will get the full commission on any future offer in the next 6 months as I will be doing the keg work moving forward"