There is no public timetable for TDCJ transfers, and that is by design.
When a transfer order is in the system, the general window you will hear is somewhere between 30 and 60 days. But that range is not a guarantee and it is not a schedule. It is simply the approximate timeframe within which the transfer is likely to happen based on available transport and bed space at the receiving unit.
The secrecy around the specifics is deliberate. Transporting inmates between facilities involves real security considerations, and publishing dates, times, and routes in advance creates risks the department is not willing to take. That information is protected at every level of the process.
Your inmate will not know they are moving until the morning it happens. The standard is a 5am wake-up call telling them to pack their property. From that point the process moves quickly. They are processed out, loaded onto transport, and on their way before most of the unit is awake. There is no goodbye window and no chance to make a final call before leaving.
The communication blackout that follows typically lasts from a few days to a couple of weeks depending on how quickly the receiving unit processes intake and restores phone access. That silence is standard and does not mean anything has gone wrong.
The most useful thing you can do now is send a letter through InmateAid to the current unit so something is in the pipeline. Mail often follows an inmate through a transfer or gets forwarded, and having something arrive at the new unit shortly after he lands gives him a connection to you right when he needs it most.