Very sick dog

Hello
   
My dog Teddy just turned 16 last month.He is a small indoor dog and weighs about 20 lbs. He used to be very active but in the last year or so he has slowed down a bit but about 30 hours ago he got very sick and stopped eating and drinking.All he will do is sleep most of the time now.He does try to get up every once in a while and walks very slowly and wobley and then lays down wherever he is and sleeps for an hour or so.He also has a strange look on his face like he's in a daze sort of. I have been feeding him baby food with a spoon and giving him water with a syringe.I know he is very old but I just don't understand how he could become so sick this fast.I cannot afford to take him to a vet because they all want money upfront.Is there anything I can do to make him better or would you have any idea what is wrong with him? Any help is very much appreciated. Thank you and God bless.
   
Thanks Greg