happen to him/her
Son collègue, le Pr Schneider, ne sait pas ce qui a pu lui arriver.
His colleague, Professor Schneider, doesn’t know what could have happened to him.
— Indiana Jones et la dernière croisade (1989)
C'est ce qui pouvait lui arriver de mieux.
It was the best thing that could have happened to him.
— Fight Club (1999)
Il a dû lui arriver quelque chose en chemin.
Something must have happened to him along the way.
Qu'est-ce qu'il va lui arriver ?
What's going to happen to him?
Qu'est-ce qui a bien pu lui arriver ?
What could have happened to him?
Dis à Tom ce qui va lui arriver s'il ne fait pas ça.
Tell Tom what will happen to him if he doesn't do it.
Quelque chose de mauvais pourrait lui arriver.
Something bad might happen to him.
What could have happened to him?