Dad being dad

Ive bought my son away on holiday abroad. dad promised he would send me money for son to my bank when he was paid (thursday🤪) not received anything from him. I cant even bring myself to message and say 'hellooo remember your son?' Lol. He hasnt contributed a single thing toward, not even so much as a pair of shorts. Would you addresss it? How would you address this with a narc? 😭 honestly makes me sick