NSW DVO Expired Can he see his kids?

A no-contact DVO can be bypassed with parenting orders. That is, if your partner had parenting orders in place for him to see his kids, the DVO wouldn't be able to stop him. If he has parenting orders restricting him from seeing his kids, then the expiration of the DVO doesn't change that.

If he doesn't have parenting orders and the DVO has expired, then sure, he can go see them, but my suggestion is to contact Legal Aid or Relationships Australia and request a mediation session with the mother first. If he goes there of his own accord to see the kids, she may end up seeking another DVO against him, so it's important that he take the most civil path.

DON"T DO IT....
The ex will have a new DVO on him in no time... Lets face it, he has not seen the kids for 2 yrs and just rocks up on the very first day that he can.... She will claim the kids are intimidated of him...
DONT DO IT.
Sure he can legally, but by Monday he will have a new interim avo on him and he will be back where he started...

Did he try mediation? court?
Call Relationships Australia and do mediation.