Legal Question in Family Law in Massachusetts

I am not sure what your desired outcome is, but "the mother of your daughter" should contact the sherriff. Tell her, if she does it voluntarily, she will probably just have to meet the sherriff at court. If she does nothing, she risks actually being arrested and taken to court - possibly in cuffs, and forced to explain her situation in front of the court/judge/magistrate. Either way, the purpose of the capias is to bring her before the court and explain her (probably financial) situation. If she goes in voluntarily - this financial discussion usually happens with an attorney who's representing another party, in the hallway - no "cuffs" and USUALLY no need to go before the court.

She could also try contacting the person or business who sent the capias to the sherriff - usually the plaintiff in a civil claim. If she works something out with them, they can "recall" the capias from the sherriff.