He is 85 and knows he may not have much time left so yes if true it is very much a confession. Of what though? Like you asked what he involved or just guilty of having the knowledge all these years.
If it were a confession of what he had done, I would expect him to confess his role.
He appears to be confessing having knowledge of the atrocity, not engaging in it.
Enough that we don’t know that its unwise for people to make assumptions or blanket statements.