First look if it's worth it -- it all depends if he'll take advantage of Plat.

If he flies a lot of domestic and thinks he could do better with his upgrade rate, it might be useful. But if he's in a tough upgrade market, it may not make a difference; or if he's in an easy upgrade market, he's probably doing all right as it is, it may not be worth the extra effort to get an extra upgrade or two next year. If I look at my upgrades this year, Plat bought me one (1) additional upgrade over Gold this year.

Similarly, if he changes reward tickets a lot, free changes is a nice perk. If he doesn't change them much, it's not a huge benefit.

And if he changes flights a lot, free SDC is a nice perk as well, but only if he uses it.

So it all depends on his flying patterns. If he flies mostly int'l and doesn't do much reward travel changes, it may not be worthwhile.