Without in-service rollover, he can't rollover his 401K to an IRA.
The tax deferred portion and after-tax portion of 401K has rolled over in the same proporation. Let's say you have 100K of pretax 401K and 10K of after tax 401K, if you want to rollorver the 100% of after tax 401K you have to rollover the 100% of pretax 401K.
So it is misleading to say 税后401就等效于ROTH.