Exactly, a delta 70 call means the same put has 30 delta (minus). 40d call = 60d putI think he meant that that both "sides" had the same delta and theta. Long put, long stock has the same greeks as long same strike call. And long call and short stock has the same greeks as long the same strike put.
So the synthetic stock has a delta of 100 (or 1, however you want to put it).
Except in situations where you should exercise the call or put early, which means that call/put has 100 delta. And the same strike put/call has a delta close to 0, but likely has a little bit left. In that case the synthetic has a delta >100, but isn't a real synthetic, since you'll lose one of the legs on early exercise.