Hi mnn
Welcome to Gambling Therapy.
In answer to your last questions – no you cannot trust him – he cannot trust himself so you certainly should not.   I recommend you look at betfilter.com and install a block on your computer.
Knowledge of the addiction to gamble is the best way to cope with it.  You cannot stop your brother gambling – only he can do that and he has to want to do it.   He ***** the right treatment if he wants to control his addiction which is every bit as serious as ***** and alcohol.   Giving money to a CG (compulsive gambler) is the same as giving a drink to an ********* – it feeds the addiction.
The addiction to gamble drastically changes the reality of the CG to fit their personal perception, it is the master of manipulation and threats, it is cajoling and friendly when it wants enablement and vicious and unpleasant when it is threatened.
The addiction is divisive and seeks enablement by dividing families.  Please make sure that you and your wife unite against his addiction.  .
I wouldn’t be writing on here if I didn’t know that the addiction to gamble can be controlled and there is no age that is too late for recovery.   You have given your brother a tremendous opportunity to change but his addiction is strong.  I think it is important that you lay your boundaries down quickly and adhere to them – it is good that he knows you will not tolerate his addiction hurting you or your wife.
I cannot tell you what to do but I hope you ensure that your property and finances are secure. 
Your brother is not bad – he would never have known when he first gambled that this terrible addiction was going to be his lot in life.   By the time he might have been aware it would have been too late for a simple answer.  
I hope you will look at our Friends and Family topic forum which is just below this forum.  We focus on specific issues that are fairly common.  
There is a lot to say and I have come upon your post late in the evening but I will write to you tomorrow.