It seems so.Also the plates removed, I know it’s fair enough not to pay the rego whilst he is away but does that mean a need to take plates off ?
Registration expired more than three months
If you don’t renew your registration within three months of its expiry date, Roads and Maritime will cancel it.
You’ll receive written notification of the intention to cancel about two weeks after the expiry date, as a registration renewal reminder notice.
You must return the number plates to a registry or service centre within 14 days of the cancellation date.
https://www.rms.nsw.gov.au/roads/registration/renew/overdue-registration.html