The "Cold Crash" was done when you brought your wort down to 70 some degrees before pitching the yeast. So you've already done that.
No, he didn't. That's not cold crashing.
Cold crashing is when you take your beer in the fermenter (primary or secondary, doesn't matter) and quickly as possible cool it down to the 30-40F range and keep it there for a few days. This drops particles out of suspension and helps to clarify the beer before packaging. You do it basically when the beer ready to keg/bottle. You crash it for a few days and then if you are bottling, for example, bottle it while it's still cold.
A common follow-up question to cold crashing is, "do I need to pitch more yeast to carbonate"? The answer is usually no.