For what it's worth, my next TV will be LED.  Plasma is a dying technology and has some limitations in size (if that is an issue for your brother).  LCD is less expensive, if cost is a factor, but LED seems to provide more vivid color with much higher contrast ratios and better performance in "high speed" scenes.  I believe it has a faster "switching time" which helps reduce blurring in scenes with fast action.
Best advice.....go out and compare and pick what is most pleasing to your eye (and in the budget)!