"1. is there any way to remove the stain?"

You can try a poultice with paint thinner, but it is going to take longer than material was in contact to draw it out.
The oil in plumbers putty is not soluble in water, and alcohol will not make much of a dent in it either.

What type of granite?

Not all need any sealer, though lots of places slather it on.

The granite is Kashmire white.
I have read to use a poultice mixture and diatomaceous earth to remove it and that the poultice mixture should have acetone in it.
Also read to try Aquamix carried at Home Depot which is an oil poultice.
Another suggestion was odorless mineral spirits. Any of these three make sense to anyone?
My husband doesn't want to wait days to "fix" this problem!