You're most welcome. And you're correct about the safety pin being a modification. The original fastening was likely by means of twin metal blades which typically break after repeated bending. These were also produced with twin lugs and threaded posts, but the blade type fastening was most common. Examples of all fastening systems are pictured earlier in this thread.
From a purely collector standpoint, a badge with original fastening intact is more desirable. However, the fact that you know the story behind the badge, that it is a part of your family history, and its personal significance to you easily trump any condition issues. I'd recommend that you write down the badge's history on a small piece of paper and keep it with the badge for posterity.