Carers leave is time away from work, which protects your job while you are away. You must request carers leave from your employer. If you meet the criteria, they cannot refuse.
Carers benefit/carers allowance is money paid by the dept of social protection. The benefit is payable based on PRSI contributions, the allowance based on a means test, you can get one or other not both.
There is more information available here http://www.welfare.ie/en/Pages/carb.aspx, specifically the Information Pack and the Scheme Guidelines (which aren't included on the citizensinformation page).
The operational guidelines for Carer's Benefit state:
Qualifying Conditions in Summary - CARER A Carer must have given up work to care for a person(s) who is in need of full time care and attention and fulfil certain PRSI contribution conditions.
A Carer must also
have been employed for at least eight weeks, whether consecutive or not, in the previous 26 week period for a minimum of 16 hours per week or 32 hours per fortnight;
satisfy the PRSI contribution conditions;
be caring for the person on a full-time basis;
not be employed or self-employed outside the home for more than 15 hours per week;
not be living in a hospital, convalescent home or other similar institution;
be fit to care.
The Carer's Benefit application form includes a section to be completed by the employer.
I am in the process of applying for these now. If condions are met work must approve leave. However the state must approve leave before work can put through leave. This approval will take about 2 months plus to approve by the state (once both yourself and work have filled in the forms). If approved and work are helpful they may put through unpaid leave now and once the state approve care benefit backdated to 20th August. However given the short time frame and if you need to start asap, is unpaid leave your best option and no careers leave / benefit application best?