Enough laughs. Although I think most of his analysis pertaining PLA is worthless, he does bring up an interesting fact that he may have intentionally evade -- both Koreas have reserves larger than PLA, even when PLA's own reserver is counted (4.5 millions each). South Korea's reserve is probably of less value, due to less time in military service, but each male in North Korea serve over 3 years in the military, which is equal to a term in countries that uses professional instead of drafts.
So if unified Korea wanted to pursue Greater Korea, there is a window -- before the North Korea reserve degrade into uselessness, start the war. Instead of calling up reserve in South Korea (that will cripple the economy), call up reserve in North Korea only since their economy is worthless anyway. With North and South Korea regular army plus Northern Reserves, the unified Korea out numbers PLA around 3 to 1 -- and that is total, not only troops PLA can devote to Korean front. And with Southern economy untouched, they can sustain the war.
And US may take the opportunity to cut China down to size, now China is in numerical disadvantage...