[mrlmd1]

New GZ250 ---
The batteries are all shipped dry, to the dealers, to the battery stores, or to you by UPS. Then the container of sulfuric acid that comes with them is put into the cells from the top, then the top is sealed with a plastic strip that is placed over the holes on top of the cells. Then, these batteries MUST BE CHARGED. It is the same for all of the companies that make these batteries that fit our bikes.
They basically are almost maintenance free, you still have to check the fluid level periodically. If the level ever drops after the initial fill, then you add water, never acid again.

Kvstrobe ---
Did you try to jump the bike from a good 12V battery like from a car? Connect the cables + terminal to + terminal, - to - with battery cables and try to start it and see what happens.
If you can't do that, can you see the headlight on or have someone else look at it and hit the start button with the clutch pulled in, the sidestand up and see if the light dims.
How did your father check the battery to say it was in good shape?
To measure the battery voltage you get a cheapo tester or multimeter or voltmeter at any auto parts store or Harbor Freight or Radio Shack or Walmart or similar store, turn it on and touch the + and - battery terminals with the probes and read what it says, before and during hitting the start button. You may need someone else to help you do this because you only have two hands. It's not very difficult, and you should have one of these anyway, only costs a few dollars.
That will tell you a lot about what's happening.