I'm (33M) getting married (31F). I would like alcoholic Brother (31M) with my groomsmen, but unsure how to proceed

So my girlfriend(31f) and I(33m) decided to get married last week. We're keeping it somewhat traditional so I'll still propose at a time and a place of my choosing (the suspense is killing her lol).

Anyway, I have a brother(31m) who I would love to put on my wedding party. Not as the best man, but certainly on the party itself. The problem is that he is a very serious alcoholic. He's 31 now, and it started to get really serious in his early 20's. Here's some background information.

He’s tried college, culinary and tech school, but flunked out of each of them due to alcohol. He has also lost several jobs due to drinking, and has not had a full time job for more than a week since 2014.

The problem really exacerbated in 2014 when we lost our father in a tractor accident. He continued to live our Mother (who was also an alcoholic). He didn't work, didn't go to school, and would occasionally steal from her to buy more.

Our Mother passed away last year on May 8 (which was ironically Mother's day). He moved in with me and a lot of those behaviors continued. He didn't get a job, despite my pressuring to night and day. He stole loose change from me to buy alcohol, he got into my closet and drank a bottle of whiskey that I had specially made for me in Ireland. On multiple I would come home from work and he would be blacked out drunk. Living with him in my apartment was an absolute nightmare.

My sister and I did everything we could think of to help him. We took him to AA and Alanon meetings. We took him job searching, even creating an uber account so he could go to interviews etc before he could get a car. We eventually learned from the folks at Alanon that trying to help someone who doesn't want the help is futile and will only start affecting your own mental health.

Eventually I came home one night and just said that this situation is not working, and we'll have to find alternative arrangements for him. I gave him a month, and we were able to find a small one bedroom apartment nearby. I was able to co-sign the lease, and he is paying rent with a $40K life insurance policy that we received from the passing of our Mother. My Sister helped him get a car with money from the same life insurance policy. So right now he is on his own to make his own decisions.

Unfortunately these behaviors are continuing. He isn’t working, or doing anything to get a job. He is impossible to get a hold of because he ignores his phone both sober and drunk. And his apartment is trashed and disgusting. He goes on benders of 3-4 days and is completely dead to the world during those stretches. Everytime he promises to do something for us he lets us down.

So here’s the dilemma. I love my brother and want him to be one of my groomsmen. I don’t know if he is capable enough, or reliable enough to be one. Should I set some rules and stipulations? Is the risk too great to have him on at all? Has anyone run into a similar problem? If so, how did you handle it? TL:DR I’d like my Brother to be one of my groomsmen, but I don’t know if I can trust him due to his alcoholism. How best to approach this?