I might also add, your son (regarding his entitlement to social welfare benefits) is likely to be much better off living away from the family home.
In his current position, his entitlement to Unemployment Assistance is subject to a means test. According to the rules regarding that means test, his level of 'Benefit and Privilege' are assessed. That is, the value to him of living with his parents, as he is under 24 years of age.
If your son was living in rented accommodation, his level of Unemployment Assistance would probably be re-assessed to a higher rate, he may also qualify for Rent Allowance to help with the cost of his accommodation and he may also qualify for a medical card or a GP Visit Card.
On the other hand, if he wishes to return to work, there are a broad range of incentive schemes, training courses, Jobs Clubs, etc. available that can help.
Before making any further decisions, a good start might be for your son to call into his local Social Welfare office and ask for the Information Officer. They can help provide information to him on his current situation and on other benefits that might be available to him.
He might also consider calling into his local Citizen Information Centre or telephoning the Citizens Information Phone Service (Lo-call 1890 777 121 Mon-Fri) for free confidential advice and information on maximising his income.
I hope this has been of assistance.