It isn't that bad of a build (for soloing), to be honest. The synergy is pretty good. Paladin and Rogue synergize well due to Divine Grace and Evasion. That means the Rogue will have awesome Evasion, and their low Fort/Will will be much better due to the boost from Charisma. Sorcerer and Paladin synergize pretty good as well, since they both rely on Charisma. Combined, it is a potent combo.
The only thing I see as a problem is how he was doing it. In a build such as this, you'd assume that Strength and Wisdom were the "dump" stats and Charisma, Dexterity, and Intelligence were the preferred. However, since he was meleeing, that means he was either a Finesse type or a Two-Handed Weapon Type.
I had a similar build back when the game was level 12 max. I thoroughly enjoyed it, but it got rather annoying trying to explain why I did what I did. I'm planning on starting her up again, but I'm having too much fun with my other "Paladins"
Rogue/Paladin
FvS/Paladin
Paladin/Sorc
Sorc/Paladin/Rogue
And no, I totally hate Paladins...really. =-)