What she wants and thinks for herself is more important than our suggestions or advices. Every person is grown differently and has different level of patience. You can't decide for anyone what s/he should choose. Someone might had a good relation with her MIL can't decide for the other what she should be doing without knowing her circumstances. I for example is living with my in-laws but I was never obliged to do so. It was my own consent to live and spend some time with my husband's family bcauses I was now a part of it. I am basically from a different city and I am completely independent to go and visit my parents whenever I want. I am never directed by anyone on how long should I stay. Even my husband has given me all the authority to decide for myself where I want to live while he is in Canada. So apparently I am not eligible to give her suggestions that it will be okay to stay with your MIL for few more months because I have no idea how influential her MIL is, unlike my case. I hope and pray you get out of this situation sooner without making anything difficult for yourself and your relationships. This is your test, brace up! All the best!
P. S. It is very hard to live without husband be it your parent's house or in laws :-(