Translation:Dein Sohn trinkt Milch.
Can we use "eure" in place of dein?
Is it acceptable "Ihr Sohn..." if you are addressing the person formally?
Yes, it is.
Why isn't Ihre Sohn... an acceptable response?
"Sohn" is a male word so you would use "Ihr Sohn".
I thought accusative make possessive was "deinen". Any thoughts?
Yeah, whh not deinen?