You must be drunk to my friend. That is not correct grammar.
*too
You must be drunk to my friend
actually that is incorrect grammar...I believe you meant to use the adverb ‘too’, acting as a modifier to the predicate phrase ‘must be drunk’, whereas you actually typed ‘to’, a preposition that in your sentence implies some heretofor unmentioned friend of yours who considers me drunk...but perhaps that’s what you really meant...