Yes, the Beto unit at Tennessee Colony is a TDCJ state prison facility. Being sent there rather than an ISF means he is serving his violation time in a full prison setting rather than the shorter Intermediate Sanction Facility program that was initially recommended.
This does happen. Recommendations made by parole officers or review boards are not always the final word. Bed availability, classification decisions, or administrative factors can result in an inmate being placed at a different level than what was recommended. ISF beds fill up, and when they do, parole violators can end up at a standard unit instead.
The 90-day recommendation being overridden by a Beto placement is frustrating, but it does not necessarily mean he is serving his full original sentence. He may still be on a revocation period tied to the violation rather than being fully re-incarcerated to complete the entire original sentence. His case manager or parole officer can clarify the exact terms of how long he is expected to be there and whether a specific release date applies to the violation period.
If there is any question about whether the placement is appropriate or whether he should have gone to an ISF as recommended, that is worth raising through his attorney.