My son probation was revoked due to not meeting with probation officer, not paying fines and failing 1 drug test

He was told that he had to maintain steady employment- due to have a felony he could only get certain jobs. The PO Knee this and told him as long as he was at work, he was within his guidelines. However, when she came to his house and he was at work, she penalized him for this. Also, he was required to pay court cost and fees, he was told that he had until the end of his probation to pay this, however, he was penalized for not paying them. He missed several appointments with his PO, however, he called her to let her know why he wasn’t there (work, illness, lack of transportation). Also, he tested positive on 1 drug test, it was identified that he had marijuana, cocaine and prescription meds. The prescription meds were due to a car accident that he was in (documentation provided) and he admitted to the other drugs. The suggestion was for him to go to A&D classes, however, the judge revoked his probation and sentenced him to 3 years.