You can set up a V-connect account and fund it for any number. Mail the 1st page of your cell phone bill to your inmate -- make sure it has a name, billing address, account number and the phone number that you're trying to get approved. Also, make sure it is not a pay-as-you go or pre-paid phone.
Since the phone is not in your name, your inmate will need to list the name of the cell phone account holder on the form he fills out to get the number approved and will submit that along with the bill. The cell phone I receive calls on from my husband is in my mother-in-law's name and that has not been a problem. Good luck and hopefully you will get to talk to him soon!