Yes, if she is available for work, she should sign on, if for no other reason than to receive credited PRSI contributions. This could have impilcations for pension entitlement, and for other benefits she may be entitled to in the future, although if she's not been signing on for more than 2 years, then she'll need to receive at least one paid PRSI contribution before she can sign for credits.
There are a couple of other education/training schemes that include time when you are receiving credits in the qualifying period, but they're limited.