As far as I know gathering a video and a screenshot evidence for the purchase, asking the buyer to buy it with friends and family and asking him to add in the description "I BOUGHT A DIGITAL ITEM AND I WILL NEVER MAKE A DISPUTE" has a very little chance of the buyer creating a dispute.
Second option is you asking the buyer to create a dispute and canceling it by a screen share or doing it yourself with teamviewer because PayPal only allows you to create a dispute once for each payment.
Hope that helps.