[Grammar] You are the one who don't understand

[Nikitus]

Hello.

Are the following sentences grammatically correct?

"You are the one who don't understand. There is a hobo in the hospital and I don't know his condition. Unfortunately I don't know if relative of him is helping right now. That's why I ask you to tell me the room where he is. And I tell you that I will not leave until I know the information I'm requesting."

 

[Tarheel]

Hello.

Are the following sentences grammatically correct?

"You are the one who doesn't understand. There is a hobo in the hospital, and I don't know his condition. Unfortunately, I don't know if a relative of his is helping right now. That's why I asked you to tell me the room where he is. And I tell you that I will not leave until I know the information I'm requesting."

Yes, the grammar is fine.