moving to Ireland

Hi all.
I would like to find out one thing by your help.
The couples would like to move to Ireland. A husband is an EU citizen but wife has no EU citizenship.
The husband gets disability allowance in Latvia, they want to move here in Ireland,but his wife can only stay 90 days in Ireland legaly. Husband can not work due to health circumstances, therefor they are not able to exercise EU treaty rights.
What are the options for his wife to stay and live here ligelly with long term.

You do not need to work to exercise treaty rights, having medical insurance and sufficient resources can assist.

thanks for your reply.

they want to move here for good and as far as i know one of them has to be exercising eu treaty rights in order to stay