Probation violations do not work like a new arrest, and that distinction matters for understanding what comes next. There is no bail hearing, no bond to post, and no way to get out while waiting. He will stay in county custody until he appears before the magistrate or judge who originally sentenced him. That is the person who has authority over what happens next, and that appearance is the only path forward.
What happens at that hearing depends on several factors, and a first-time violation for a meth-related issue is not the worst position to be in, though it is not without consequences.
The judge will look at the nature of the violation, what specifically triggered it, whether it was a failed drug test, a missed appointment, a new arrest, or something else. A positive UA or a technical violation is treated differently than a new criminal charge. For a first-time violator with no prior history beyond the original offense, many judges are willing to consider options short of incarceration, particularly if there is a substance abuse component that can be addressed through treatment.
Age works neither for nor against him specifically, but 38 with a first offense and a meth-related violation fits a profile that drug courts and treatment-based probation programs were designed for. If his jurisdiction has a drug court or diversion track, his attorney should be pushing hard for that option at the hearing.
The most important thing he can do before that appearance is have an attorney present who knows the judge's tendencies and can make the strongest possible case for a treatment-based resolution rather than revocation and incarceration.