Find a missing child by phone location

This is a very important project for us. The wife of one friend takes his daughter and went to the USA (we live in Puerto Rico). Nobody knows their address but he still communicate with his daughter via a wireless phone number. He already contracted a local lawyer but the process is slow and he's basically crying every time he thinks about his child. We wanted to help. Although we have the option of going to the FBI, we intended to resolve the situation more quickly. The reverse lookup tools that are available on the market doesn't work because only give us basic information about the phone and not the PRESENT location. We need to find that child so the authorities will get to her quickly and press charges to the mother. If you're an expert in this field, PLEASE help us. There's a father suffering. We'll give the phone number to the freelancer that demonstrate his ability to work based on his experience. We're looking for the exact location (not approx.). Thanks!!! Note: We think that this is a few minutes work for someone experienced. All need to be in a legal way. I'm a veteran in this website and I'm not going to affect my reputation for an illegal project so please, all by the rules.