Could be worth a try

if

you have enough space

they grow in full sun

the foliage isn't too prone to get powdery mildew or other fungus stuff

and it is not just some seedling

you could start by pruning, defining the main framework, removing dead wood,

what shape dos it have roughly now, like

trained to an espalier or rather some single post thingy?

Add some kompost and ocasional waterering

next spring I would appl more compost, fert, whatever, and water in dry spells.

not sure what your climate/wheather is like.

it would probably take another season in order to get the first grapes, that would be fall 2018.

and even then it could happen that you don't lik their taste.

still, if you have fun experimenting, I would go for it.

IF their rootsystem is still intact, it should respond nicely to a little TLC

any chance to see a pic of that plant?

Does it look like it was taken care of in the past? Like trellis and structure or is it just running around all crazy like its never had proper support?