Auto loans over 60 months are not the best way to finance a car. And yet, 43.5% of new-car buyers in the third quarter of 2015 took out loans of 61 to 72 months, according to Experian.
DNA Tribes is correct that siblings can and do have very diverse DNA. Your autosomal DNA is a random subset of your mother's and father's DNA (50% from each parent). Two siblings will not have the same results for the same reason that they do not look exactly the same. They do not get the exact same 50% from each parent. Even identical twins don't have exactly the same DNA (only almost exactly the same).
When the alleged father is not available for testing, you can choose the sibling DNA test or the aunt/uncle DNA test. Both of these tests will give a probability percentage, and are not as conclusive as a paternity test. However, out of the two I would recommend the sibling DNA test.