We are family
We have an extended family Slack group, with various sub groups for parents/adults and kids. All school related emails go to a specific email account which distributes them over Slack on a keyword basis and we have a shared Google calendar that pings updates to everyone. It works for us better than bits of paper or conversations that switch between text/twitter dm/Facebook Messenger/Whatsapp depending on who's involved.
Would that we did something similar at work- I even get emailed a spreadsheet of dates my for diary, rather than actual calendar invites.