By agreement between you, you could create a Right of Residence in your favour which would not change the ownership but would give you security.
On your brothers death, if he leaves the house to you, you will, probably/possibly, have a CAT liability.
If he leaves his share of the house to someone else, you will, probably/possibly, have a CAT liability. But you will have security.
You need proper legal and tax advice, specific to your circumstances, to properly understand your position.
mf