You can also directly drag all the people in your friends list into a new group chat. If they are displayed in the group, they are still your friends.
Find the settings in WeChat-General-Group Assistant-Select All, and copy and paste the message and send it. Whose name has changed color, it may no longer be your friend, just delete it.
You can also send a circle of friends to see if your friend likes you and judge whether he deleted you.