JMO I think the mother and stepfather/mom's bf are naive about the law. They seem honest and forthright, a hardworking family just trying to make a living, raise their kids, and he at least is acquiring citizenship. The lawyer has their interests in his mind. If someone is charged in DA's disappearance, their defense is going to be that this family lost their child or did something to her, may make unfounded claims that they are bad parents, they could even have their children taken by CPS. The lawyer's job is to protect the interests of the parents including from aggressive defense lawyers, so he is just looking out for them, believes it is better if he speaks on their behalf (I agree.) It may also be that LE has suggested that they only say certain things and not other things.