Rufus needs a wheelchair.

UPDATE:  I SUBMITTED RUFUS'S MEASUREMENTS AND NEEDS.  Eddy's Wheels for Pets does not have any used chairs but can build him a custom chair for $650.  When Rufus no longer needs the chair I will donate it back to Eddy's and they can adjust it for other dogs.   I greatly appreciate your help and any assistance is appreciated.  Thank you!  Thank you!  Thank you!    (Story below)

My best buddy, Rufus, who is 13 has lost much of his ability to use his back legs but still acts like a puppy and loves to run even dragging his back legs.    I would love to get him a wheelchair so he can live his last years running.   Like any dog,  he's changed my life.   He introduced me to all outdoor sports,  hiking is my favorite,  and keeps me laughing.   I want to give back to the old man who changed my life.   Anything appreciated.   Thank you for considering! 
Kim : )