Messages not received by android phones

Starting less than a week ago, my texts to my husbands android stopped being delivered. It looks like it sends but he doesn’t receive. Even in a group chat w other iPhones they see what I chat but he doesn’t.

we’ve tried everything posted:

• checked for block on both ends
• toggled iMessage, SMS, MMS and restarted
• reset network settings (to factory)
• deleted and perm deleted EVERY message
• checked apple DB to make sure his android number isn’t there
• installed all updates to IOS

I do not know anything else to try.