回複：求大家幫助, 出出注意!

1) Very likely, yes.

2) If they divorce now, even not 去移民局報案, she is not likely to get Green Card.  On the other hand, if your sister-in-law married your brother on good faith, try to get her GC (if she wants).  Good deeds will be rewarded.

3) If the divorce can be negotiated, no need to get a lawyer.