Toad is not doing good

Toad over the last couple of weeks has been not eating and looks bad. He started feeling bad a couple of weeks ago. He stopped eating dry food about a week ago and Nanci has had to give him water with a syringe. Now tonight we can't find him. We where down stairs watching TV and he came down and meowed. Nanci thought he wanted in to the room with the cat boxes. She took him in there and he didn't act like that is what he wanted. I went up stairs and noticed he had peed on the rug at the bottom of the stairs. Nanci picked it up and followed me up. Then we went back down stairs for a short time. Then Toad and Nanci went up stairs and Nanci was feeding him wet food and Nutircal. She left him to eat at the top of the stairs shut the back door and came down stairs to finish watching a show. We where only down there 5 minutes or so. We grabbed the dirty dishes from supper and headed up stairs. The back door was standing wide open. The wind apparently blew it open. Toad was nowhere to be found. It's about 9:30 PM so of course it's dark out side. We searched the house and the yard, no Toad. He is too weak to jump the fence. But, we looked everywhere inside and out. Nanci is worried sick he just went somewhere to die. I just hope Tina will find him when she get's home tonight.