Pay-Related Social Insurance (PRSI) contributions, which are a percentage of gross reckonable earnings/ income in a week are paid by full-time employees, part-time employees and self-employed people. The PRSI contribution normally incorporates the health contribution and the employment and training levy, and is not payable on unemployment assistance or on any other social welfare payment — regardless of whether or not the recipient is also a medical card holder.
The person to whom you refer would not be liable for any PRSI deductions, provided he has no other income apart from his unemployment assistance.