Senior Centers sometimes have "loan closets". The one in my father's community provides for loan equipment for up to 3 months. I don't recall if there's a charge, but if so, I think was nominal.
Another option (which I haven't explored so I'm just guessing here) is to contact an organization such as the Paralyzed Vets. Wounded Warrior could probably use the equipment, but I'm not sure that their services provide for that. I think their focus is primarily on monetary donations.
Contact your local Area Agency on Aging and see if there is some type of local medical equipment bank that can take donations that they then loan out to others.
Another option (which I haven't explored so I'm just guessing here) is to contact an organization such as the Paralyzed Vets. Wounded Warrior could probably use the equipment, but I'm not sure that their services provide for that. I think their focus is primarily on monetary donations.