Mother died almost a decade ago at a church sponsored activity (negligence involved). Question on statute of limitation and tolling. Missouri.

A little less than 10 years ago my mother fell from a horse and struck her head on a pickup truck, she died shortly after from brain damage. She almost certainly would have survived if she was wearing a helmet.

Looking up the wrongful death SOL it looks like it's 5 years in MO. However, my little brother was 11 at the time (he's 21 now). I heard there's something called tolling, where if the "discovery of harm" was by a minor, you can wait until he's at legal age (18 I would think) to file a suit.

So he would have turned 18 a little over three years ago. Is there still a chance for a successful law suit in this case? Or would the SOL make this a lost cause?

Is it like the tolling age 18 plus the SOL? Or would we have had to file at the latest when he was 18?