I don't know if this helps but I beat him in pro mode with the shotgun. Just kept firing!

just shot him with my sniper....10 times...haha

Buy a rocket launcher (if you have enough money) blast him with it and finish him off with the tmp.

i really dont even think its possible, when i fought him i had 4 first aid sprays most of my guns up to par and a couple of granades (more like 4 or 5) and when i was through with him i had nothing in my inventory i was completly empty.

You may want to tone down the difficulty, recently tried taking him on on hard mode: epic failure.

You can use a hand granade or two when he's on the floor, then when he is unattached to his legs, he'll be hanging on the ceiling and structures, you can go up and start using the shotgun in his face several times.

You can also complete a RGY herb here, I think the red and the yellow are upstairs and the green down next to the entrance.

it totally easy i finished it 100000 times to kill him i kill him easly coz i have alunsher rocket lunsher in one hit he dies in no time colect money to buy lunsher and collect tresures as many how you can then buy rocket lunsher