Do you think people should be able to own and have their own nuclear weapons? How about biological weapons? What about murder? Should that be legal?
If you said no, then you do agree there needs to be some "nanny state regulations". We only differ on where the line should be drawn.
When people "grow up", they realize that the general populace isn't too bright. The world is filled with nutjobs, idiots and crazies. People who are downright evil. People who are sociopaths. Letting the "free market" sort them out is a fairy tale for the young and children.
I don't mean to sound condescending or harsh, it's just that I was once a libertarian myself (in my early to mid twenties.) I came to realize what a horrible ideology it was and when you see people making the same mistake you made, you can't help but try to help that person out.
I'll let the results speak for themselves.
Unless your brother is immortal, he will eventually fall ill or suffer an accident. Such is the nature of life. Some people live long & healthy lives, others get cancer at 25. You simply cannot know the future. Shared risk, in the greater scheme of things, is preferable to the alternatives.