16. Through the right focus $F$ of the ellipse $\frac{x^{2}}{3}+\frac{y^{2}}{2}=1$, draw two perpendicular chords $A B$ and $C D$. Let the midpoints of $A B$ and $C D$ be $M$ and $N$ respectively.
(1) Prove that the line $M N$ must pass through a fixed point, and find this fixed point;
(2) If the slopes of chords $A B$ and $C D$ both exist, find the maximum value of the area $S$ of $\triangle F M N$.