so a few weeks back my kids dad wanted to take the kids to Texas for the summer,I said no because…

so a few weeks back my kids dad wanted to take the kids to Texas for the summer,I said no because when we broke up he was in and out would go months in between with out seeing them,and never took care of the kids fulltime plus I didn't feel safe with out the courts involved ,he hasn't seen them,just dropped their tablets off at my dads a week or so ago and didn't see the kids my son asked to see him but I think he left my sister said his fb says living in Dallas...idk what to tell my son he knows I didnt want them going but what dad leaves with out saying by or responding when I asked why he hasn't seen them