Almost certainly yes, and the pattern here is the part that matters most.
This is not a first violation anymore. The first violation already resulted in a second chance in the form of a 30-day sentence at a rehab facility rather than straight prison time. That was the court extending leniency a second time, giving him a structured environment with support and resources instead of a cell. Picking up a violation inside that facility means he violated the terms of his supervision in the one place specifically designed to help him not do that.
From a judge's perspective, that sequence tells a clear story. First violation, given rehab. Violated in rehab. At that point, the argument for alternatives to incarceration becomes very difficult to make. The court has tried supervision, it did not work. The court tried treatment placement, it did not work. What typically follows is the imposition of the original suspended sentence or a significant portion of it, in a standard correctional facility rather than a treatment setting.
The honest framing from the original answer is worth sitting with. Someone who keeps violating in increasingly structured environments is not yet in a place where they are ready to make different choices. That is not a moral judgment; it is an observation about readiness for change. Rehab only works when the person inside it is genuinely willing to engage with the process rather than just waiting for the 30 days to end.
If and when he does go back, the most useful thing you can do is encourage him to use whatever programming is available inside and to go into the next supervised release situation with a genuine plan rather than good intentions.