Sorry for your loss.
The payment by you is not a tax deduction.
The receipt from his estate is only taxable if it exceeds the class threshold brother-brother which is €43,400.
Any payment by you of his estate costs would be deductible from any inheritance and only the net inheritance would then be reckonable.
If, as you say, the amount receiveable is only going to cover your costs then ther is likely to be no net inheritance.
Going on that there are no implications for your tax return.
Was the funeral grant from DSFA paid ? if there was an entitlement to that you might be reimbursed partly that way.