Depends on your part in it. If you isn't the father to either of them, then there's no "real" relationship between them. Your exwife's son would be the "stepfathers stepson" to your current wife's son's.
If you're the father to the current wife's son then the other would be "his father's stepson".
If you're the father to the exwife's son but not the current, then the first son is "the son of his stepfather" to the current wife's son.
If you're tha father to both then they're half brothers.
neffu
Your half-brother...
your son and your brother's son will be cousins
your son is your brother's nephew, and your brother is your son's uncle
your son and your brother's son will be cousins
your son and your brother's son will be cousins
Your mother's son is your brother or your half brother.
Your wife's brother's son would be your nephew...
Your son's wife is your daughter-in-law. Her brother is your son's brother-in-law, but the English language has no word for a relationship between you and him. You are not considered to be related to him.
Your brother's son is your nephew. His wife is your brother's daughter-in-law but is not related to you.
You would call your wife's elder brother's wife "sister-in-law."
If your wife's son is also your son, then he is your brother's nephew and your brother is his uncle.If your wife's son is a child from a previous, or subsequent marriage and is therefore not your son, he is not related to your brother unless you have adopted him. If you have adopted him, the relationship is the same as if he were your biological child.
If your wife's son is also your son, then he is your brother's nephew and your brother is his uncle.If your wife's son is a child from a previous, or subsequent marriage and is therefore not your son, he is not related to your brother unless you have adopted him. If you have adopted him, the relationship is the same as if he were your biological child.