This requires strategy with a good criminal defense attorney. As is typical with exes it's a he said-she said and may require the case be set for trial. As for probation, again, may require a contested hearing to prove he did not commit the offense of interference with a 911 call. But without knowing the entire story, I don't know how to properly comment on your question.
If he's on probation for four years, its for a felony--not an fta. His probation will almost certainly be violated because of the new case. He needs a good defense attorney trying to get him out of this.
Macy Jaggers's answer to a legal question on Avvo does not establish an attorney-client relationship. Ms. Jaggers offers everyone a free consultation to discuss their case. Feel free to call her office at 214-365-9800 to make an appointment (phones are answered 24 hours) or visit her website at www.macyjaggers.com for more information about her services and recent victories.
Whenever someone is on probation and they receive a new charge it's always a serious matter. Any violation of probation can result in jail time. It's best to hire an attorney sooner rather than later.
Austin Probation Lawyer
My answers are intended only as general legal advice and are not intended to create an attorney-client relationship. There is no substitute for a full consultation with a local experienced criminal defense attorney. For more answers based on my 19 years of experience visit my website, www.austincriminaldefenseattorney.com