Q: Where do your grandpa live? Why is “do”? I thought “does” とはどういう意味ですか?
A: If the sentence is correct as you heard it, it could be that the actor is trying to imitate an ignorant person. Sometimes, a writer or actor will deliberately use poor grammar to indicate an uneducated or stupid person.


Q: Me and grandpa と Grandpa and I はどう違いますか?
A: It is more polite to say the other person first ("Grandpa and I" or "Grandpa and me").

Both "Grandpa and I" and "Grandpa and me" can be correct, it depends on the context.

Take out "Grandpa and" and then go with which ever of the two ("I" or "me") is correct.

"Do you want Grandpa and me to go get that for you?" is correct because "Do you want I to go get that for you?" is not correct and "Do you want me to go get that for you?" is correct.

"Grandpa and I just got back from the zoo" is correct because "me just got back from the zoo" is not correct and "I just got back from the zoo" is correct.

I hope this helps :)
Q: I loved my grandpa very much. we played football, looked at the stars, and most of all we went fishing. と I used to love my grandpa very much. we used to play football, look at the stars, ,and most of all we used to go fishing. はどう違いますか?
A: There's different tenses, and both are not grammatically correct. In the first part, you wrote it in present tense. The last one was in past tense.


Q: grandpa は 英語 (アメリカ) で何と言いますか?
A: QAの全文をご確認ください
Q: grandpa and grandfather? は 英語 (アメリカ) で何と言いますか?
A: QAの全文をご確認ください
Q: because his grandpa was passed away or because his grandpa passed away? は 英語 (イギリス) で何と言いますか?
A: the latter


Q: if you told grandpa the truth, he would have a heart attack. この表現は自然ですか?
A: Hart = heart
Q: I had met my grandpa and grandma after long time and we ate a Japanese foods which was seafood. I was moved by those foods. この表現は自然ですか?
A: I would understand what you were talking about if you spoke or messaged that to me, but the natural way to say it would be:

I met with my grandpa and grandma because I haven't seen them in a while. We ate Japanese seafood. I loved the food.
Q: "It's what I can do for you to the least for your grandpa." この表現は自然ですか?
A: "its the least i can do for your grandpa" sounds better. is that what you're trying to say?
Q: ‎My grandpa's made me a will. この表現は自然ですか?
A: Your pronunciation is really good.

We usually say, "My grandpa (put me in his) will. " Is this what you mean?
Q: How do you address your grandpa's mother?
A: There is no fixed term in conversation. Most families have a pet name. In our family it is "great granny".

In general, that generation (parents-parents-parents) are the Great-Grandparents.