Stimulus checks for prisoners

My son is in a California prison, and I've been able to submit applications on-line that have allowed him to receive (into an account in his/my name), stimulus checks on both rounds so far. (For those who don't know, most prisoners are eligible to receive these, and for many it's an incredible boon. )

My son has tried to help other inmates to make applications but many of the inmates don't have family that can help them do this, and to make applications themselves seems overwhelming. Does anyone know of any organizations or law firms that are offering assistance to prisoners in applying for stimulus checks?