So thats what it meant!

Visited my dad two days ago and was looking at him tombstone when I finally realized what his special signature represented.

Its on top of his tomb and looks like incoherent scribbles. After staring blindly I made out that it was a "V" followed by an "R" and small lines for Rosales.

Wow, after all this time I got it.

Hehe well I guess I'll have to wait before I can ask him.