[_paralyzed_]

sometimes you can charge a lipo in nimh mode at a very low amperage to revive an over discharged lipo. Under 3.0v/cell is over discharged.

Since each cell should be atleast 3.0v a new 4s should be 12v minimum. Your extreme low initial voltage reading is indicating 3 cells were fried when you got it, and the 1 that was hanging on died in your care.

I'm sorry to say it is a lost cause. (assuming you checked individual cell voltage at the balance tap- if the voltage at any of the balance taps is more than the whole pack voltage the problem is an internal solder failure)