Some banks have low penalties when withdrawing early and clear early withdrawal terms such as Nationwide UK (Ireland) while other such as KBC have far more stringent early withdrawal terms and others such as RaboDirect have very unclear penalty terms.
There is no legal obligation for KBC to release the funds.
KBC can, if they really want to, release the funds early but they will need major persuasion to do so.
A sob story helps. Why does your Mum need the cash? Is it medical reasons? Can you produce evidence to that effect? etc.
An in-person meeting helps too, their HQ is on Sandwith Street. Have you spoken to them face to face?
Escalation to management helps. Has a KBC manager looked at your case?
Hopefully, the above works. Failing everything, you could ask KBC for a personal loan equating to the value of the term deposit using the term deposit as collateral for the loan.