Probation Service Role? From Mum B

Hello Prison Widow 

I am glad to see that the blog is back! 
A few weeks ago I spoke with my son's probation officer because I had some concerns. The answer I got was that my son was responsible for his own actions and he and only he can make changes. I hit a brick wall and the probation officer had very little time for me. I have a question for any probation officers that might read my comment. 
What exactly do probation officers do? I thought they were assigned to help offenders? If my son's probation officer cannot offer me and my son advice then surely he would be better off signing on at the local police station instead of catching buses to and fro to attend probation? It's a pointless exercise and a waste of money. 
Much to my son's disapproval, I went to probation with him one time and no disrespect to his probation officer, it was "hello are you OK and see you again next week". I do not understand their role at all. 
I honestly thought that probation officers played a part in supporting offenders so if any one from probation reads this, please clarify what your roles are. Thanks in advance.