Only if Byakuya let him enter the Kuchiki family. In Japan, when women of noble families get married, one of three things happen - assuming that she is marrying into a family of equal cast and power, she remains a "Hime" (princess) and she probably has a choice of which families princess she is considered. However, if her husband is from a lower cast or even a noble family of power prominence, IF the union is properly sanctioned, then her family would "adopt" her husband. Otherwise she would just be cast out.