Same name

[BookishZen]

My grandads name was Montague Charles but everybody called him Charlie. Had DD been a boy this would have been my top choice. However SIL and BIL have just had a little boy and named him Charlie. Ideally I would still like to honour my grandad in some way but I don’t like either of his full names or the nn Monty. Does anybody have any ideas of other shortened versions I could use? Would it be weird if I used Charlie as a middle name, I think it would but I’m interested in hearing other people’s opinions.

So your brother uses Charlie as a first name and you would use it as a middle name= absolutely fine, no one would bat an eyelid.
My nephews middle name is my dads, had I had a boy I would probably have wanted the same middle name, doesn’t matter.

No , not weird at all. My DS's middle name was used by SIL as her son's first name.

SIL didn't actually realise when she named her son (my DS is a lot older) and was slightly put out when she found out, but it didn't bother me at all.

Personally I wouldn't like a family member to use my DS's name even as a middle name, but his name isn't too common or honoring any relatives so it is slightly different as you want to honor your grandad.
As an option you could use another nickname for Charles such as Chuck / Chuckie?

I think you can use Charlie as a middle name in these circumstances.

Totally fine to use it as a middle name imo

Completely fine to still use as a middle name

Just use Charlie as a middle name

Montague is fab. How could you not use it.