While a soccer player she did not have much road racing experience according to Athlinks.com records--a 4 mile race she ran 3 times with the last time in November being a much slower pace than prior races. I think most runners run a few half marathons before attempting their first marathon. Running in high temperatures are difficult for anyone but it can be even more so for a runner with little racing experience and possibly no long race experience who has been training in the very cool weather we have had almost all spring now in the Great Lakes region. She may not have known how important hydration is during a long race especially in 70+ degree weather.
The forecast for the race is below. 70 degrees at 7 AM, 77 by 9 AM, 79 by 10 AM. Dew point of 61 and relative humidity of 73% at 7 AM.
https://www.youtube.com/watch?v=3xdBuZda7GY