Help with Keegan or with game settings

I am just starting T.I. and am stuck at the regular campaign Keegan battle. I have been unable to defeat him.

Is there any way to lower the difficulty or turn off the max attempts?

So far I have failed to kill him after 30 attempts.

If I can't get past this then the game is already a failure for making it impossible to continue.

I am level 41. If I come back at level 50 will Keegan still be the same level or will he also be stronger?

Is there any way to store gear that we find along the way?