There are a few issues here.
wbbs advice is true, if you bought the property as joint tenants,which means that you are both joint and severally liable for the mortgage.
If you bought as tenants in common, then you are both only liable for half the mortgage each. You should check with your solicitor which is the case.
It is normal for couples to buy as joint tenants, but often solicitors advise people buying with their friends or siblings to buy as tenants in common
Also, you can't just change the names on the deeds of a house. It is a legal document which defines the ownership of the house, and it has a mortgage attached.
Removing your name from the deeds effectively means giving your half of the house to your brother. This is a gift and may be liable for CAT tax.
Also, the mortage means that you are not legally entitled to change the ownership of the house without paying off the mortgage, or the mortage provider agreeing to the sale. In the current climate, they will only allow your brother to own the house if he is assessed for the full mortgage.