It's worth trying anyway, isn't it? To see if she'll get thrown off, and even if she doesn't, Tidus still can't attack with the thing right there in the way - it's a potato between the both of them. A potato that just makes Jecht amused, while Tidus is just getting frustrated!

'Not bad,' the man says, while Tidus shouts, "Just get away from him! I can't fight him with you there!", but Jecht still speaks to her as he throws out a hand. '--Can Granny stop this?'

And his features mutate as his palm comes down to face Tidus, hand shifting into a claw, and a burst of energy slams into him, throwing Tidus backwards - grabbing for the edge he nearly tumbles over, his sword laid to the ground.

Danger, Danger, need help from our own special Granny as illusion!dad starts walking over to Tidus, who's scrambling to pick himself back up.