In every thing give thanks: for this is the will of God in Christ Jesus concerning you.
1 Thessalonians 5:18
Notice that this scripture instructs us to give thanks in all things, not for all things. When tragedy or temptation strikes, we are not to thank God for them. He is not their author. He's the One who provides our way of escape from them. And that's what we're to thank Him for.
If you read the four Gospels, you'll find that Jesus never gave thanks for sickness or death. Instead, when He encountered them, His response was to overcome them by God's power. So give thanks as Jesus gave thanks—not for Satan's activities but for the victory God has given you over them.