It can be fixed. First detect the cause of damage, vulcanization is repaired with repair instrument, broken frame is manually repaired; Lead-acid battery voltage down to 9V can find a charger to charge a try, if it is not caused by the battery plate fall off can be recovered to pay attention to the charging as far as possible not fast charge, with a small current slow charge effect is better if the full charge time is not long battery voltage reduced to 12V below is the plate has a problem, to replace the plate.
Not anymore. It has a static voltage of 9v
Use a density meter to measure the concentration of acid in the battery liquid, if it is too low, you can add the battery liquid, and then charge. If it still doesn't work, the lead plate is aging and can't be repaired.
You can try it, add the electrolyte and repair it with a smart charger, and the repair is unlikely