Ghosted

How do you explain to your kid when an adult ghosts them?

My husband’s and mine “best friends” ghosted us. They randomly started canceling all plans and we reached out asking what’s up because we thought maybe they were going through some hard shit, but all we got was “it’s over.” We’ve been friends for 10 years, they’re the ones who get our kids if we die per our will (guess we gotta update that). My kids are 5 and 3 and talk about them fairly often, my 3 year old talks about going to the zoo with them. My husband and I are fuckin heartbroken (and pissed), and extra heartbroken for our kids. How do we explain this to them? It’d be easier if we had a reason, even if our friends blamed us we could say “they got mad because mom and dad did this, be better than us to your friends.”