If it's about your kids like that, you should always reply.
If it's not about your kids, and doesn't contain a question, generally you shouldn't reply at all. Ditto that texts that attempt to R-talk, or to suck you down into the pit.
If it DOES contain a question (say about some family logistics or finances of some sort), then wait a few hours and respond cheerfully with a "Sorry, just saw this -- busy day! Yes, I can thus-and-such, ________, just let me know -- thanks! Talk more soon. "
