He is not referring to absentee mail in ballots. Which in Ohio at least, under normal circumstances, are only sent to registered voters who request them. This year however, due to the pandemic, they are automatically sending the absentee ballot requests to every registered voter. Those who are not registered to vote presently need to request one for this election after they register. That is how I understand the process here in Ohio. Of course, I could be wrong.
The absentee ballot has a verification process involved in voting by one. In Ohio, you must provide a form of identification that verifies you are who you say you are. Does not have to be a photo ID however. The form you use to request to vote that way, is filled out by the voter and then mailed back to your local voter administration, then you will receive a ballot back by mail, if you pass the verification process.
He has specifically stated those are ok. It is the type which some want to use, where a ballot is mailed out to every one by the mail and then people fill them out that he is concerned about. I agree with his concern. There needs to be a good verification process involved with voting, even more so when it is done by mail.