Ok, so you had decided that also. Then I feel that was the correct judgment.
How did you learn your grandfather changed his name? What is the source? Is your source entirely reliable?
Where did your grandfather live? Can you share more information about him Danny? You are still quite "close" and private with your facts.
To find the descendants you seek in the present, one needs first to post as much as one can about your grandfather's siblings in the past - and about your grandfather himself. We can't leapfrog from the past family to the present descendants.