I am so very sorry for your family's loss.
I've had a friend have it happen to a English Pointer, and a different person to their lab.
Without a necropsy, there is just no way to pinpoint the reason.
Not all those who wander are lost.
Life is just a leap of faith.
Spread your arms and hold your breath and always trust your cape.
Two things define you. Your patience when you have nothing, and your attitude when you have everything.