We would suggest downloading the Dánta agus Amhráin and working on some of these.
As this resource is for Irish language schools, we would suggest downloading material for Rang a Dó or Rang a hAon.
Songs
Colaiste Lurgan have translated and performed many pop songs in Irish. The lyrics to these have been posted online by this site: https://songsinirish.com/artist/tg-lurgan/
We suggest listening to some of these songs. Your child could try to learn one of the songs using the printed lyrics.
Google “anam an amhráin”. They have produced beautiful animated videos to traditional Irish songs, which your child could watch and learn.
Vocabulary
Use either Memrise or Duolingo to develop their Irish.
10 minutes a day work on those would be very beneficial.
Twinkl has a list of high frequency Irish words.
The list is the top 1-200 words. You could begin with the first 10 words and then reducing/increasing the amount of words per day according to your own child’s needs.