Bipolar disorder

Hello, My name is Anne. My 26 yr old son has been diag.with bipolr he is also addicted to drugs/alcohol.  He has been to many rehabs over last 10 yrs.  We did not address his bipolar until about 19 mos ago when we read some books.  My husbands way of treating our son is to ridicule,threaten ect. when he does not act as expected. He thinks after reading the book he should understand and take care of problem. What is right should we do tough love and refuse to help or should we get him  a better psychiatris? He has trouble with law also. My mind is mush I can't explain what I'm asking. Hope you get the gist. Thank you