Wish Book: Drowning is the leading cause of death for autistic children. The YMCA hopes to expand a water safety program that’s changing the dynamic.

Jason Foreman was on a casual stroll with his 4-year-old son Lucas near Cupertino’s Stevens Creek Dam when it suddenly turned into a nightmare.

He had looked away for just a few seconds to pull his phone out so he could snap a photo of his son enjoying the outdoors. When he looked back, Lucas had stepped into the deceptively shallow-looking water — and disappeared underneath it.

Lucas Foreman, 9, from San Jose, waits with his father Jason before Lucas’ Safety Around Water swim class at the Southwest YMCA in Saratoga...