This and other sentences like it are said to have no meaning to be true or false. It's like asking "who is the widow's husband?" There are things God cannot...
do due to His nature like lie, break a promise, split into two essences will himself out of existence, etc. Does this seem reasonable to you?
If the person asks if this makes God NOT "omnipotent", then paste this...
Omnipotence has historically/classically been understood as the ability to perform any task consistent with His (God's) character and essence...
Any other definition is not how God has revealed it to us.
If the person asks where's the proof for God/Jesus/Christianity, go here.