How to reinforce brick pavers driveway edge?
Use a dry mix of about 60/40 Portland cement and masonry sand or bags of playground sand. ( You may need to adjust mix) I use a drill with a stirring paddle and a 5 gallon bucket. Remove 4 or 5 rows back remove original underlayment replace with mix and replace pavers.  Spraying some water on mix right before laying pavers will help it bond faster.  Remove and replace small sections so that you keep everything in place. I would also stack the pavers I remove so that they go back into there original place. I would not use concrete because of the aggregate. Take your time and good luck.