Bad time?? Not really coz I don't live with them...not even with my husband!! I've started ignoring everything. If he talks in a negative manner to me..I just say..call me later when u'r in a good mood!! Believe me...it works!!
Iksa, the next time your SIL creates drama, be the bigger person and stay calm. After she is done with her false over-the-top emotional speech and shedding her alligator tears............calmly tell her "As a new addition to this family, I only want to fit it in, not to be a threat to anyone. I have no desire to cause problems for myself or my marriage or anyone else by instigating arguments with you. I am not trying to steal your brother away from you. As Muslims, all of us should consider that Allah is WATCHING everything we do and say. So, for HIS sake, we should be mindful of our actions and try to be civil."
Who knows? Maybe the simple and basic point of "Allah watching everyone" will motivate your SIL to think twice before she lies about you again in the future. Subtly put the fear of God in her ;)