Could this not equally well be "my grandfather is George"? If not, how would you translate "my grandfather is George"?
While I don't think you'll see this I'm going to leave the answer here for anyone else who wants to know. You are exactly right the Arabic sentence could mean both
I have no answer but the same question
Saw that you have a current streak so figured I'd reply to your comment to answer the question for you
Isn't "my" given by a suffix ك?
No, it isn't. my is given by the suffix ي and your is given by the suffix ك