If the person is on PRETA, he has exhausted entitlement to Jobseeker's Benefit (PRSI contribution based payment, not means tested) so is on a means-tested payment.
The means test for PRETA is the same as that for Jobseeker's Allowance. Income/savings are assessed as follows:
Savings:
First €20 000 is disregarded
Next €10 000 is assessed at €1 per €1000
Next €10 000 is assessed at €2 per €1000
Balance is assessed at €4 per €1000
The amount arrived at is assessed as weekly means.
For example, if a person has €40 000 in savings, the weekly means assessed are €30 per week.
This assessment is also used if the person owns property (excluding their own home) - the capital value of the property is assessed.
The weekly pension is also assessed as means and is deducted € for €.
You mentioned that the man's wife isn't working due to illness - if she is in receipt of SW in her own right, it will also affect the amount of PRETA, as the husband cannot claim for her as a dependent.
The full rate for 2 adults on PRETA for 2008 is €329.10. From the figures provided and assuming that the wife has no income of any kind, it appears there may be something missing.
If there is no other income in the household, he should contact his local Social Welfare Office and ask for a review of his claim, to confirm that his entitlements are correct.