When a probation officer files a violation, the case goes back to the judge who originally sentenced your boyfriend. The PO submits a formal complaint to the court outlining the reasons for the violation, and the pending felony charge is the basis for that complaint. The violation itself is the legal mechanism the PO used to bring him back into custody while the new charge plays out.
The pending felony charge and the probation violation are two separate legal matters that will run simultaneously but through different processes. The violation hearing goes before the original sentencing judge, who reviews the PO's findings and decides what consequences to impose. Options range from time served in county jail with modified probation conditions all the way to revoking probation entirely and requiring him to finish the original sentence. What the judge decides depends on the nature of the pending charge, his overall compliance history, and how seriously the court views the violation.
The pending felony charge moves through the criminal court process on its own timeline, separate from the violation hearing. That is likely why you cannot find it easily yet. If the charge was recently filed, it may not have fully populated in public court databases. Contacting the Clerk of the Court in the county where the alleged offense occurred is the most direct way to find out what has been filed and what the case number is.
Having an attorney handling both matters simultaneously is essential. The interaction between the violation and the new charge requires a coordinated legal strategy, and the outcomes of each can affect the other in ways that make independent navigation very difficult.