I have to be honest and say i'm no fan of colored gravel, but if thats what it will take to make this tank HIS and not YOURS, i say more power to him
Every thing else in the tank seems pretty well thought out and looks pretty good (since in my head im imaging the tank with dirt and not gravel)... maybe if this planted tank works out for him, the next Real Plants planted tank you guys create, you can work on it together and make it a high-tech tank with all the bells and whistles...
Oh and by the two of you, i mean you helping him move everything where he wants it, like Takashi Amano's helpers, while your son acts as Takashi Amano and stands to one side pointing and directing where everything should be for the best look