I Have A 17year Old Jack Russel. He Is Refusing

I have a 17year old Jack Russel. He is refusing his food. I've tried all different good. Hard , sift gravy but no. He will eat the odd treat but not often. He is blind deaf but just walks around the house constantly. He has had a couple episodes where I think he us gone..he falls down with all 4 legs stretched out for a couple minutes but then comes back and starts the walk again..I'm thinking it might his time but really not sure. Any advice? Please