I doubt they will be expelled, but Antonin is going to make sure Padma at least sees exactly what they have wrought.

My slim hope is that it will be a wake up call for at least one of them. I think Padma is beyond hope, but Seamus, maybe not. He seems to believe the lies he has been told, but has some level of real feeling.
Before he got too close to Padma, he helped classmates in need even when he disagreed with them. I'm thinking the crucios in year 2 where he helped both Ron and someone else to get help.