Responses
Actually he can, the author wrote a couple of short stories and yeah, in the first one Grisia did get drunk. http://www.princerevolution.org/sunknight-main/sunknight-chapterlist/ You can find the other short stories and the other novels here if you're interested.
Aaa but theres a big error here Grisia would never get durunk for he is the drinking fiend who rivals his master!!XD