In Florida, it is law that a child under 16 wear a helmet. I don’t see anything in MSM that says he was or wasn’t wearing one. I don't know about lights on a bicycle but that would be common sense from dusk onward. If it was routine for him to ride after dark, he may have had the reflectors, lights and other safety features as the bike was relatively new, or new to him anyway.
He was a strong healthy young boy from all appearances, so he could probably pedal pretty fast. If he was on his phone while riding or was being chased by someone, he could have easily lost control, crashed into a tree or barrier, rolled, etc. That doesn’t necessarily mean it was an accident tho. A perp could have caught up with him and that interaction could have led to his death.