I'm sorry to hear about your brother-in-law. I've met many people who have had similar issues with alcohol. And yet, myself and many people are also able to use it in balance, in a way that contributes positively to our well-being.
If I could pick something, it would probably be legalization + social support for people dealing with addiction, along with actual consequences for people who do bad things while on drugs, as opposed to what the police do now, which is basically throw up their hands and say "we cant put every heroin addict in prison".
I think the biggest issue I have with Heroin personally is how it seems to totally consume so many peoples lives and how completely unable they are to recover. There is a reason people say heroin addicts never really recover, they just take breaks.
Heroin and opioids may be slow and gradual, but then it’s an insta kill.
Maybe food for thought though about how society views direct vs indirect causes of death.
If heroin was legalized, it could be standardized at a non-variable purity, and other methods of intake would be more popular. Lots of people were going blind from alcohol consumption during prohibition also.