An Arizona fire department is formally honoring a 14-year-old boy who recently helped save an elderly woman with dementia after she wandered miles off course amid potentially lethal temperatures, saying the teenager demonstrated “heroism … quick thinking and compassion”.

Royal Cothrun was riding his bicycle in June in the town of Gilbert when he encountered Theresa Morgan as she struggled to walk through 103F (39.4C) heat with a grocery bag dangling off one arm and a purse on the other, according to authorities as well as reporting by the local news outlet KNXV.

Cothrun later told KNXV that he slowed down to speak to Morgan because “she just looked like something was wrong”.

“I knew it was hot,” Cothrun said to the outlet. “She was sweating.”

It turned out that Morgan, who turned 76 in July, had just been diagnosed with dementia. She had become disoriented on her way home from visiting a grocery store, which constituted a serious emergency given that being in heat over 100F for an extended time can cause life-threatening illness.

“I don’t think there’s any apartments around here – I can tell you that,” Cothrun could be heard saying in a video of the ensuing conversation with Morgan, which his smart glasses captured. “Yeah, I could look it up on my phone if you want me to.”

Cothrun eventually accompanied Morgan to some shade, where he helped her remember her son’s telephone number. He then called her son, Jeff Morgan, and let him know about the situation with Theresa.

The boy stayed with Theresa until Jeff and Gilbert’s fire and rescue department arrived to take over and get her to safety.

The climate crisis-driven heatwave that scorched parts of the US with record temperatures in June through early July had played a role in the deaths of at least two dozen people, according to information released by officials.

And in a report first published on 9 July, Jeff told KNXV he believed Cothrun’s kindness may have actually saved his mother’s life.

“It’s incredible, really, what he did,” Jeff said to KNXV. “Just so lucky, so fortunate, that he ran across her and he cared enough to stay with her and to take care of her.”

In a statement to the Guardian received on Friday, the Gilbert fire and rescue department echoed Theresa’s son, explaining that confusion or sudden disorientation is a serious warning sign that someone may be on the verge of heatstroke – which can be fatal if not addressed promptly.

A battalion chief with the department added that the agency was “proud to recognize Royal’s heroism” and planned to honor him at an 11 August town council meeting.

“Royal’s quick thinking and compassion not only protected a vulnerable member of our community – but also highlighted the real dangers posed by Arizona’s extreme heat,” Ryan McHugh, the Gilbert fire and rescue battalion chief, said. “His actions remind us all to stay alert and look out for one another, especially during the summer months when heat-related illnesses can become life-threatening.”