Birthday Poems for Father-in-Law: Wondering how to wish your spouse’s dad a happy birthday? Don’t think of him as your husband’s or wife’s dad. Imagine how you would treat him if he were your own father. Take ideas from this post to create your own original rhyme which you can scribble out as a personalized greeting on a card. Send sweet texts, cute emails or funny posts on Facebook if you are not going to be able to meet the old man on his birthday. Even if you don’t bond well with him, his birthday is a good day to start building bridges in your relationship. After all, nothing in life comes close to the happiness that radiates from the chatter of a happy family.