My son is in jail for violation his probation his on probation for 5years for a marijuana charge and he and while on probation he got a dui and the p.o put a pending on him what would happen to him and what type of lawyer should I get

Your son should get an attorney, he may need two separate ones, he needs one to address the DUI. Since if he is found guilty of it, he may well have to serve serious time in prison for violation.

Then a criminal attorney to address the violation of probation.

It may be the same, but in many areas ( I know Atlanta GA) there are some attorneys who do nothing but DUI and are good at it.

But assuming he was DUI and they have proof that will stand up in court, really not much to do but find out what the judge will do on the violation.

If the DUI was drinking, not from drugs it will be better for him.