1- Give her patience and boost her morale. Remind her Allah will compensate her for all the difficulties she is going through. Allah appreciates her efforts.
2- See which of her in laws is the most understanding and have a talk with them. Don’t them she told you. Tell that person: bases on my observations, it seems she is struggling and a lot of pressure is being put on her, or that she is being abused. Try to make this person understand the situation and work with this person to help her. This abuse needs to stop, so do your best to work with someone in the family to address the situation appropriately and creatively.
3- Let her try to spend less time with them (creatively in a way that won’t cause an issue with them). She can keep herself more busy ti avoid spending time with them.