not to spoil things but I just went onto baby names and put in the boys name Tony and got this
Meaning: Short Form Of Antony not frank
Ian, you are not spoiling anything.
You will notice that from the outset we searched for Anthony/Antony. However, it is not unknown for people to assume a different name or pet name.
We just wonder why brother Frank is not mentioned in the obituary.
I think you wrote that grandma kept the two sides of her family separate (or similar).
Perhaps whoever gave the information to the obituary was unaware of brother Frank, who had been dead for some time, or was misinformed or indeed there was another brother somewhere of an unknown age/birth.
Mistakes happen.
For example, we keep referring to Frank Walter (birth name) but his baptism shows Frank Lewis - perhaps an error at the time - who knows.