I am a non-custodial parent of my 14 year old son whose mom moves to another state in 30 days, can I stop her from taking my son?

Broke, miserable and unable to support herself, she quit waitressing here, is moving in with a new boyfriend in another state, and plans to get a new job as a waitress there. My son has been on my medical insurance for 6+yrs, including dental and orthodontia coverage, yet has never seen a dentist while in her custody. In March, he stayed with me for his spring break, arrived with an infected ingrown toenail which required antibiotics to kill the infection and reduce the swelling, then surgery to remove the toenail, and stayed another wk (missing school) to recover. Can my ex move out of state and take him without my permission? He wants to stay with me, says he can't talk to her about anything without fighting, yet clearly does not want, nor should be expected, to decide because he does not want to upset her.