I'm so very glad that you have thought of the option to help your brother unconditionally.
Since my last posting on this, I have helped somebody else who is now in accommodation, work and so unbelievably happy. He keeps saying "somebody help[ed me!".
I have also had my 70th birthday last week and have 3 children of 43, 40 and 36. I have helped all 3 hugely in their adult lives and all their cards reflected this and said "thank you for helping me". This meant as an adult and not as a child being brought up. That vital help at a point when people are going under can be crucial.
As I write, I am helping nobody and all are on their feet and independent with gainful lives.
Will I help again in the future? Yes, certainly - if it feels right.
All the best and hopefully you will sleep well with your choice!