The phone in your parent's pocket is either a lifeline or an attack vector. This checklist makes sure it stays the first one.
Silence Unknown Callers. Settings, Phone, Silence Unknown Callers, On. Sends unknown numbers to voicemail. Enable Spam Text Filtering. Settings, Messages, Filter Unknown Senders, On. Disable link previews when locked.
Enable Caller ID and Spam. Phone app, Settings, Caller ID and Spam, On. Block unknown callers. Phone, Settings, Blocked numbers, Block calls from unidentified.
Register on Do Not Call Registry. donotcall.gov or 1-888-382-1222. Set up a family code word. Only family knows it. Any call claiming to be family that cannot provide it is suspicious. Defeats the grandparent scam. Establish the 24-hour rule. Any request for money, gift cards, or personal information gets a mandatory 24-hour wait. No exceptions. Legitimate requests survive a day. Scams do not.