revival

Last night I took a loaf of my whole grain sourdough to a get-together.  There a friend told me that his mother still has a piece of his deceased grandmother's sourdough in the freezer, and can't bear to discard it.  He's possibly interested inreviving it.  He asked me for advice about how to do so.

It could have been in the freezer as long as a decade, though.  That's a long time.

If it's possible to revive a starter after this long a freezing, what would be the best method?

I presume it would be best to cut off a small piece (like 1 oz) and feed that.