My apologies on misreading! I’ve been working insane hours lately 
If your friend has the time/money/interest, I would recommend seeing if Gráinne Hambly has time for some Skype lessons or is doing a workshop in his area. She really changed the way I look at harp playing. She works on a more traditional approach to tune playing, as opposed to piano-style arranging. Most of what the left hand does is just outlining the melody: open fifths, doubled roots, short arpeggiations, etc. Now, that’s not to say that she does only simple stuff, but it’s a good starting point for doing a more Irish-type of playing. If you get a chance, have your friend listen to some of her recordings. She’s probably my favorite harpist.
I know both she and William Jackson, an equally wonderful Scottish harpist, do workshops in arranging and also in accompanying and playing in ensembles.