I'd believe it. I first heard of NAC on the nootropic subreddit in a past lifetime. The benefits vary, but generally it's a safe thing with a low chance of making anything worse, but a possibility to improve things. Many neurodivergent folk have written about how they benefit.
I'd give more info on the exact benefits they found (iirc OCD and rumination loops could be broken more easily), but unfortunately my memory is failing me.
Usually here in Canada it's available in capsule form which I find less effective.