my son had a 3 degree burn while and mom custody now he and foster care by her own petition as a father do i have a right

First of all, let me say I am sorry that your son was hurt.  It is not clear from your question if his mother voluntarily placed him in foster care as a result of the injury or for some other reason.  As his father, you do have rights in the foster care system.  You should make sure they know you are interested and willing to provide a place for your son.  You shoud have had a lawyer appointed for you if there is any question of abuse or neglect and there is a dependency action filed. Since your son has special needs, it would help your case with the foster care system if you are familiar with services and agencies available and able to provide any special services your son may need at home or at school.  These services are not only good for your son, but they can make it easier for you to care for him.