I am trying to finish up about 20 gals of elderberry wine that was
started by someone else. They passed away and I would like to finish
this wine. I am a novice winemaker.

The person who started the wine usually didn't follow a specific
recipe, so I am guessing they used past experience, judgement and
probably whatever yeast they could get at the grocery store. I know
they probably didn't use campden tablets. The wine is in five gal
carboys. Some appears to be still be fermenting (bubbling). 3 of 4
carboys have air locks. The other has just a cork and has some white
film on top.

I siphoned off some of the wine and measured the sg - it was about .9.
I tasted it and it was very bitter/dry. I gradually added 1 pt (500
ml) of wine conditioner (sucrose with sorbic acid) and it tasted
better. But it took the whole pint of conditioner for just one gallon.
I siphoned off the balance of the wine into small containers to
transport in my car. I have added additional sugar to the wine (heated
a small amount of wine and let sugar dissolve into) and have returned
everything to a clean carboy with airlock.

1. At this point the wine has a sulfur smell that I didn't noticed at
first. Is this because of the conditioner? oxidation?

2. Will the sulfur smell likely go away with time?

3. The carboy with the white film on top also has some "head space" -
is the film oxidation? Is that carboy beyond hope or could it be
saved?