There are many things to consider here. Money fractures families. I can share my experiences.
My father was an alcoholic. His parents loaned him $30,000 to get him out of a major jam. They were very well off, and this was affordable. My father made payments on loan every week, but did not finish paying off the loan before he died. When he died, he was 11 months sober. When his father died 5 years later, the will stated that we (the grandchildren) were specifically excluded because they had "cared for their son during his life." The estate was much greater than 4x the 30K- even accounting for interest, and this created a rift between my siblings and the rest of the family who did inherit that exists 20 years later. My father was the black sheep, and we are all tarred with it.
My brother is an alcoholic, who lived with my mother until she was moved into assisted living for Alzheimer's. Because of her dementia, we (the children) had a lot of influence on her decisions about money. We had her set up a trust for my brother for his "share" and had another sibling manage it. My "healthy" brother had total discretion on how to dispense it, and he used it for rent, car payments, and health insurance, as well as some college expenses for my alcoholic brother's daughter. Given the pain we all felt at being "cut off", none of us would have been comfortable having my brother "cut off" from my mother's will. Although the situation was stressful for all, it was the best thing for us.
I have a friend who's son is 5 years clean. They spent over a hundred thousand dollars on his rehab, and have documented the costs- these are listed in the will, and will be used to adjust his "share" when they time comes. This is the way they felt it made sense to equalize things between him and his healthy sister.
Another friend just redid their estate plan. They are dividing assets equally between their son and his sister, who is currently an addict living on the streets. Their son (now 25) will be a joint trustee with a professional fiduciary firm. This will allow him to have some discretion in the care of his sister, but will also allow him to walk away at any time if it gets to be too much.
There is no one right way to handle this. Only you can decide what you consider fair and just, and what will give you peace. Whatever you decide, I think it's important to communicate the plan- with love- to all your children, so that they understand what you are doing, and why. If you do decide to leave money in trust, I'd suggest you to give the trustee broad discretion, and not try to micromanage things from the grave.
Best of luck.