I am a former lifeguard, swim teacher, and waterpark assistant manager. If I'm thinking about the same thing, this is where they teach kids to bring themselves to the surface and float on their back until help arrives. I have 2 kids who have been in a skills-based swimming program since they were 2 months old. Although it is not an ISR program, the director has incorporated components of the program in a way that is much more gentle and gradual. The program we attend is at Energym Sports Campus in Sycamore www.energymsports.com - we've been through both "Baby Amazing" classes, as well as the "Iddy Biddy Pool School." The swim staff is amazing and worth the drive.
I have seen videos of the ISR program and think it is amazing, but yes, a bit scary for the parent. If I had a pool in my backyard or at a close relative's house where my kids spent a lot of time, I would consider the ISR program. Have you tried talking to a local instructor and asking for references?
Ultimately, EVERYONE needs to know how to swim.