First you must realize there are limits for what FFG can handle. It's ASW unit, not AA. It can handle FEW missiles.
Don't get detected in the first place. It means, go on EMCON all the time. Helo has the radar too, and good one, so use it. Helo can also detect missiles at way longer ranges, because it's high, and if you expect missile threat, you can move the helo toward it. Then you can have information about the missiles real soon and few seconds can make a difference. You can use FFG air radar, but not before the missiles are inbound.
Also you can promote missile tracks to link, if there is Aegis nearby, it will help.
And lastly, don't underestimate chaff. Fill the air with it. But you must place it between you and the missile. In DW CMs works only if they are closer to missile (or torpedo). If they are not, they don't work at all. Every chaff cloud means percentage test, and it is especially good when the missiles are shoot in tight swarm. Many times I shot 8 missiles at ship and all 8 went through one simngle chaff cloud.
Also helo can drop chaff, but only if it is human controlled
. Maybe you can try to shoot SM at it so it will lauch some :rotfl:.
Oh wait .. it's not the last thing. There are yet two important things in missile avoidance. Launch the helo if there is any onboard. It can pick up survivors or at least report there were none.
And the really last thing is: scream
