ANSWER:

Deliberately exposing her arms like this nullifies her prayers. She must ensure that it doesn’t expose her arms. Not raising her hands won’t affect her prayer, however, she should either wear sleeves underneath her abaya or tighten it from the wrist area so that it won’t go up. 

In salat when a woman raises her hands saying Allahu akbar before going to ruku and her abaya arm sleeves drop down a bit in that moment revealing her wrists and and a couple inches of her forearm is her prayer valid? If she has this abaya on should she just not raise her hands?please advise.