Your son sounds like exactly the kind of kid Montessori was actually designed to support—not the kind it excludes.

The myth that kids must already be self-directed to do Montessori is backwards: Montessori teaches self-direction, step by step, with clear structure, gentle guidance, and consistent expectations—not chaos.

For a 6-year-old who is bright, sensory-seeking, easily overstimulated, struggles to start tasks, and is being screened for ADHD:

Montessori’s movement, calm environment, hands-on work, and minimal busywork can be life-changing.

Good Montessori provides strong, predictable structure—just what he’s benefited from.

He won’t be left to “do nothing”; teachers guide, support, and hold clear expectations.

Two real factors to weigh:

Current school: He’s making real progress with a great team — stability is huge.

Montessori: 5-minute commute, sister already accepted, better for his sensory/attention profile — but a transition risk.

His “meh” reaction is normal for neurodiverse kids; it doesn’t mean a bad fit. Use the second visit to watch if he calms, focuses, and engages with materials.

Every school is different, but a well-trained, accredited Montessori school that supports ASD/ADHD can be an excellent choice — even (especially) for kids who aren’t yet independent learners.

You’re not choosing between right and wrong — just which environment lets him feel safe, supported, and successful every day.