It is absolutely repairable. I make canvas and can’t even count the times I’ve made repairs like this for MANY boats. He probably wanted to sell you a new one.
You will need a heavy duty sewing machine like the sailrite LSZ, it will do the job nicely. Just needs double canvas reinforcement.
It is repairable. However, the PVC is so UV damaged that the material at the edge of the repair will fail in short order. No professional will repair it as they can’t guarantee their work. The tension the patch will put on the existing material will just create the next rip.