People will commonly file frivolous lawsuits after MVAs, slip and falls, etc. There's no down-side for them and an excellent chance of collecting something. The only times they seem to get punished for doing it are if they're defrauding Workers Comp or the disability system. But private suits? It's far cheaper for the insurance company to settle than to go to court. Free money for them, higher premiums for the rest of us.
Your son's suit, where he will need ongoing care, is not frivolous.