Hi mnn
The answer you would like to have given would have fallen on deaf ears. 
The following is an adaptation of something I often use.   It is not recognised by professionals as a way of dealing with the addiction but it is something that many of us have used that has helped.   I hope it helps you understand your brother’s addiction a little better.
Imagine your brother’s addiction as a slavering beast in the corner of the room.    As long as you keep your cool and don’t threaten that addiction it stays quiet, although it ever sleeps. 
Your brother is controlled by that addiction but you are not.   When you threaten that addiction, it comes between you and controls the conversation or argument.   If you might find yourself in the middle of an argument without knowing how you got there – it will be the addiction pulling the strings, enjoying the confrontation and aiming to drive you further into confusion.   It is the master of threats and manipulation and you are not.   Once it is between you, you will only hear the addiction speak and because it only knows ***s and deceit, it will seek to make you feel blame and demoralize you.   When you speak the addiction distorts your words and your brother cannot comprehend your meaning.  
My CG explained it to me by saying that when I told him (for instance) that if he didn’t *** but lived honestly he would be happy, his addiction was distorting his mind convincing him that I was ***** because he truly be***ved that he was unlovable, worthless and a failure and did not deserve happiness – he was lost and fought back because he didn’t have any other coping mechanism apart from gambling.   The addiction is all about failure for the CG which has no love for the addict or those who love them.   However much your brother convinces you that he is in control – he is not.
The addiction is now in your home but remember at all ***** it is your home – the home that you and your wife have worked for, which your brother’s addiction will covet. 
It certainly sounds as though your brother has not accepted his addiction.  The addiction to gamble has nothing to do with money.   It is impossible, I think for the non-CG to know what it is like to own the addiction – we have an understanding of money that the CG lacks.   Money is just a tool – a means to an end and the end is the gamble.
It is sad but your brother’s addiction would have known that family would care – it is a selfish addiction and as long as it has enablement it will grow.
Determine that you will not have the addiction in your home.   You have every right to lay down rules about staying with you – it would be right to tell him that an understanding of all that you have done for him is that he will seek help.
Click on ‘Resources’ at the top of this page, Select ‘World’ and ‘Gambling Help’ and ‘Search’.   Scroll down to Gamblers anonymous – Twenty Questions.   If you print them off it might help you brother to realise that just ticking 7 yesses means he has a recognisable addiction – the chances are he could tick all 20.   Put them where he can see them – it is best, I think not to confront him with them because he will deny he has a problem.   He might screw them up and throw them away but hopefully he might not.
Keep posting