Sorry to hear it, that story is played out over and over. I don't remember the specific numbers but of the motorcyclists who died in Texas last year the vast majority were NOT wearing helmet, about 65% if I remember correctly.
I saw one other stat that of all the crashes 19% hit one cheek or the other.
Helmet make a very, very big difference. The rest of the gear is really icing on the cake to prevent road rash and broken/bruised joints.
Road rash can lead to Staff Infections. I'm sure Nelly or MadMan can add more to that topic.
Please do yourself and your loved ones a big favor and always wear your lid.