transfer of farm
"I seem to remember reading an article somewhere that if he inherited the property before the age of 33, his tax implications would be lower"
The age you are thinking of is probably 35. If your brother is a "young trained farmer" - i.e. under the age of 35 and holder of a "green cert" or equivalent qualification, he gets a stamp duty exemption. With stamp duty on a transfer of farmland being 4.5% between blood relatives, this is a significant relief.
As other have already pointed out, there are no inheritance tax consequences either way.