Convincing older dog to use pet steps

Between his arthritis and some side effects from his anti-seizure meds, my dog isn't able to hop up on the furniture quite as well as he used to. So I went out and got a set of pet steps for the couch and another one for the bed, thinking that he would be glad to have some help. But he won't use them! I tried showing him how they worked by walking up them myself, and I tried luring him up using treats, but he won't have anything to do with them. I hate seeing him get frustrated trying and failing to jump up onto the furniture so I'd love to train him to use the steps, but I'm out of ideas (he's very motivated by treats, so I thought for sure that would work!) Anyone have any other ideas?