I deleted all.my social.media AC even linklnHe only did a Google search on you. My grandfather can do that, it's hardly "techie".
Make sure your social media accounts are private and people who are not friends of your immediate friends can't add you. FB has this function. I'm not sure about IG, I think IG you can definitely make all your photos private. Then do a quick search on Google and other search engines on yourself and various versions of your name which you've ever used online that you can think of and see if you appear anywhere. Do an image search also in case any of your pictures have been cached, then delete/privatize those pictures. Do it for your family if you need to. While I'm on this topic, I want to remind everyone how terrifyingly dangerous it is to put pictures of your children on social media. So don't do it.
He's now trying to get to your contacts to embarrass you. The blitz will last for a while, he's either bored/not enough customers, so very free.