sibling vs. husband

it's currently 1 a.m. where i live, my husband and i live with my family. at the moment my younger sister is causing her own problems. she won't leave our room because my husband wont escort her to her room. she claims it's cause of her fear of the dark, ive just gone and turned on all the lights all the way up to her room. yet shes still here fighting with my husband and causing herself panic attacks. she started punching herself and hyperventilating until she started crying. it's exhausting just being in the same room as the two of them. she wasn't like this when he and i weren't married.. ug..