Why do we humans commit suicide?
It's an age-old question,,,and while literature has many examples of those for whom love was central issue, current steep rise in overdose deaths in North America is a subject that has intrigued me often. It also seems to me that that lack of human connection is so often the main culprit.
And yet the people is one 'thing' that we know is increasing everywhere.

While I am not sure what led to the decision in your brother's case, perhaps we all can provide some level of Meaningful Connection to Each Other to fulfill the need within our circle of interactions.

In the meantime, we all have Our Lives demanding us to be looked after and if we slip on it we can't avoid the consequences. Life never has easy answers and we EACH can arrive at the best one that matches our unique lives.

This is how I try to start my day...what else is the choice? (and with eight decades on this planet I, too, have had my share of ups and downs including a friend's fate that ended the way your brother's did.

I think there is a book along six? stages of grief,,,maybe u find it helpful.
Wish you well, fellow human,