1)
What is "Tiskefehu"?
1.
Rashi: You overpower him and force him with Your strength, and he goes from the world.
2.
Malbim: This refers to his hope. In man's youth, his hope girds him with strength. It depicts his world as if he will always succeed; he goes with this hope.
2)
How is Hashem "Meshaneh Fanav"?
1.
Malbim: In old age, his face changes. His beloved hope does not recognize him, and You send him from it; it is distanced from him.
