can she use our old firm

What is the name of your state?idaho
three years ago we hired a lawyer to help find and gain cutody of my husbands children. this year my husbands ex-wife's sister-in-law used the same firm to gain custody based on hearsay and deny hubby court ordered visitation to his kids? Were still in court and he informed me today he can keep this in paper conflict for more than a year. Is this legal?

Who's kids are you talking about? confusing post.

this is who they are

They are my husbands kids and his ex-wife gave them to her brother and sister-in-law without notifying my husband

I am a little confused by this but it sounds like a major conflict of interest type thing. By going through the same firm, they are privy to confidential information.