Modern society is not so particular. For various reasons, it is normal for younger brothers to get married before older brothers. Just write couplets as usual.

If we must highlight the situation that "the younger brother got married before the older brother", then write a couplet for reference (for the time being):

Love and agreement, talk about fate, Mo Yan successively;

Brothers, friends, brothers, there are always priorities when preparing to get married. ?

Cross: Everything will be fine.