teenage nephew kicked out by dad, living on cold streets

[Sarahs_Dad]

      Apparently my wife's ex-brother-in-law kicked our 16-year-old nephew out of their house in Indiana (suburb of Lousiville, KY) because he didn't like his son's girlfriend and didn't want them to see each other anymore.  This Summer he offered for us to take the younger 14-year-old nephew, who got into trouble with the landlord and school.  Then the dad sent him to live with his grandparents. (These are different nephews than our other, younger two who are in foster care/guardianship in CA.)   About 9 years ago the nephew's dad/my wife's ex-brother-in-law won custody from my sister-in-law who left her other son in a mental hospital in Little Rock.   My wife was close and like a mom to our oldest nephew (homeless one) when he was little.  My wife, her sister and parents haven't seen either boy until I found them on My Space and we drove up and united with and visited them this June and Labor Day weekend.  The 16-year-old dropped out, was expelled or suspended from school and was supposed to be working on his GED.   In addition to him being in a gang, we're concerned about him having the basic necessities, including a place to live.  In the few weeks since his dad kicked him out, he has stayed with friends, his girlfriend, grandparents, in vehicles and outdoors in a park, but sooner or later he might wear out his welcome.  Hasn't the dad criminally abandoned or neglected him?  My wife tried calling to talk to the dad or stepmom but their phone has been disconnected.  In the last year or so they have moved a few times.  So we don't know the current address.  My wife stays in contact with the oldest nephew through cell phone and his girlfriend.  We don't want to involve CPS/DHS because they would probably worsen the situation and may cut us off from our nephew(s).  Lately we've been seriously considering emancipation or the oldest nephew coming to live with us, but we're already broke this month.  So that we could enroll him in school, consent to medical care, his employment, and otherwise have loco parentis authority and control over him wouldn't we need an Indiana court order giving us custody, foster care/parenthood, or guardianship?  I don't think just a simple written consent from the dad will be sufficient.