What is the primary objective though? This one seems fascinating offer.
The objective is to both of you win through this offer although it's still vague on how does he mean keeping the account active. I am assuming here that it will have to trade every single day, keep the account have positive balance until 4-5 weeks after registration or deposit. This needs to be cleared up as well.
I am not sure how the escrow would work, would be willing to pay the full amount after trade is placed but not sure how I would guarantee the money would be kept inside for 4-5 weeks.
Deposit the exact payout amount into your chosen escrow, for example $170 for 5 referrals (I just assume most users will prefer to deposit higher amount here) and instruct the escrow to release it to your referred users after 4–5 weeks, or once they met to the terms you've set. If you choose the right or trusted escrow here, even the community will agree that it will be a guarantee the money will be kept. There's already a user who offers the service and check as well the thread he linked, they are trusted escrows although double check it too.