Everyone bullied El
El knew Luke abandoned Elena three years, and El never had any opinion about it.
Elena never told him anything about Luke, and El respected his little sister so much.
He wouldn't ask anything if his little sister didn't let him know. It didn't mean he was happy to see his little sister's situation.
Who wants to have an indifferent brother-in-law for their little sister? Marriage should be based on love, not for business purposes.
El didn't know what to say because his marriage also didn't base on love. His most beloved father matched him with Misa Cloudy.
(It is sarcastic when El says his most beloved father.)
My most beloved father never loves any of his children, and his father only thinks of his children as a marriage tool.
El already made a promise to himself a long time ago. He doesn't want Misa to experience the pain that his mother suffered. He treats Misa gently and spoils her to the sky.