If my ex was sentenced for felony spousal abuse, he was sentenced to 5 years’ probation in 2012; he got a DUI and went back, what will happen?

A number of things could happen. The DUI would be considered a probation violation. Depending on how close he is to completing his probation, the courthouse and jurisdiction where the felony conviction occurred and the demeanor of the judge, you ex could be sentence to 60-90 days or more in county jail and his probation would be reinstated. He could do no jail time and his probation extended. He could do some county jail time and his probation reinstated and extended. Or the judge could revoke his probation entirely and re-sentence him to the original jail/prison term. It will all depend on the judge.