Need help-repairing old suede couch

You can buy curved needles that will work and sew it up.

I read the information at hunker.com and I agree that it is a good way to go. Your tear looks like it would require a curved needle. Fray Check is a good suggestion but if I may make one little tweak ... after the FrayCheck has dried hand stitch a piece of scrap fabric to the inside of the tear. You only want to stitch it to one side of the tear at this point. Now to close the unwanted opening with the curved needle, push the opening closed and try to catch the scrap of fabric behind the sofa fabric with your stitches. The reason you sofa rip there is because it is a stress point and the fabric weakened over time and thru use, having a small piece of fabric on the inside of the repair will help to keep the stitches from pulling out of or thru the weakened sofa fabric.

V Smith has it right. You can buy a package of assorted upholstery needles at Walmart. There are 4 different sized curved needles and one straight one. I would use quilting thread, doubled to do the stitching. It's stronger and will hold up better. As V said, reinforce the edges with some sturdy scrap fabric. You might want to knot it off every few stitches in case one breaks, then you won't have to sew the entire thing up again. And be prepared to pull hard! Good luck.