How safe is my son? Also I don't have the money to be sending him any I'm sure this will affect him in a negative way can't he work?

Safe is a relative thing. Only he can make things worse if he misbehaves. If he is able to follow rules without an attitude then he will get through this using his social skills like when he was on the street. Most inmates have to work. The hours are usually not long and you can imagine the pay is tiny, but it'll keep him in a routine (that is very safe) and even buy some extras at the commissary with what that brings in.