For me, Christmas is a prime opportunity to passive aggressively tell my loved ones what I hate about them and/or their lifestyle. Take for instance, last year, when I decided that my family's dog was sooooo annoying, so I took a chance, made a change, and bought them a new one. (A Chinese Crested that I refused to let my mom and dad call anything but "Kanye" or a gender ambiguous pronoun.) But enough about me. This is about you, your boyfriend, and how you're going to alert him of your concern regarding his appearance/grooming habits. Via Christmas gifts.
Honestly, buy him enough of this shit, force him to hang out with you, your family, and Kanye/they for 24 hours straight, and you two gentile sons of bitches will be in great shape come the new year! Thank me later.