I have a 2000 Hyundai Sonata. It has a start problem but it has also been

sitting for about a year or so. Help? The details: My daughter used it for a few years but gave it back because it was a 4 cyl and didn't have the power she wanted. I used to start it up and drive it around a bit until one day when I went to start it - it wouldn't start. I used our battery charger and got it going and drove it around. Then when I came home and turned it off it wouldn't start again. FINALLY, my husband looked at it and the brackets that go around the battery knobs were broken. By this time it had been sitting a long time. He replaced the battery and the leads. Put new gas and the gas additive in and it won't start. It cranks over or tries to. He then used starter fluid and it starts for about 30 seconds and then dies. What is anyone's best guesstimate. I am open to as much information as I can get. Thanks, RJ