Shock incarceration, which is what New York's shock camp program is, exists specifically to get eligible inmates home faster than a standard sentence would. That is the whole point of the program, and if your boyfriend was accepted into it, that is genuinely good news.
The standard New York shock program runs six months of intensive military-style programming inside the facility. It is physically and mentally demanding by design, covering drill, physical training, discipline, substance abuse treatment, and life skills. Inmates who complete it successfully are released to a period of intensive supervision in the community rather than serving out the full sentence behind the wall.
With a 1 to 3 year sentence and two months already served in jail before Elmira, he has a head start on time served. Factoring that in alongside the shock program timeline, a reasonable estimate puts him home somewhere around the 12-month mark from when this all started, possibly sooner depending on how quickly he moves through the program and when his completion date lands.
The two months in jail on the violation should be credited toward his commitment, which works in his favor.
The most important thing right now is that he takes the shock program seriously and does not wash out. Inmates who fail to complete the program get returned to the general population to serve their sentence the standard way, which eliminates the early release. Staying focused and disciplined through the full six months is what brings him home on the faster timeline.