87 buick wont crank after changing alternator

Hope Im in the right group for this old car. Two weeks ago I was driving my late dads 87 buick and the altermater light came on. He did not drive the car very often before he passed away except like ever few months. When I got back home the car would not even turn over battery was so weak. I finally had time today to change the bad alternator and charge the battery and all the car would do is turn over but not crank. I tried this for over and hour letting battery charge back up then pump or hold has pedal but still would not work. I sprayed some starting fluid in the throttle body and it would crank for about a second then shut off. Any ideas on what to try? Im not a mechanic but did not want to put a lot of bucks into a 19 year old car to have it towed to a garage. Any ideas I can