I agree completely with Mewcreation, evolving your machop is the best way to go, given the info that you gave. What I did in my Sapphire is, I had two Lombres and alternate them using fake out on "Dad's" Slaking. Since Lombre has low attack and fake out is weak, EV train (attack) and troll "dad" using the fake out when he sends out Slaking. Plus Marshtomp can learn decent fighting moves, if you gotten brick break already make Marshtomp learn it. That will help a lot. Those three things should work out for ya.
Here's two ways to troll dad:
The first one is the way I mentioned above. Two Lombres, even better two Nuzleafs (if possible), use macho brace to boost all stats when leveling up. After getting to the desired level (and stats) alternate Lombres/Nuzleafs between the loafing around; don't forget to use Fake Out. Evolving your Lombres/Nuzleafs into Ludicolos/Shiftrys will help out, but got no new or better moves after evolving, so I'm leaving that decision to you.
The second one is getting a Pokemon that can learn Thunder Wave. Get a Pokemon that can learn the move, like Pikachu, get Makuhita/Hariyama that knows SmellingSalt. Use your Thunder Wave Pokemon to paralyze and alternate Makuhita/Hariyama, use SmellingSalt to increase power. Of coarse SmellingSalt will cure the paralyses, switch with the Thunder Wave Pokemon with Makuhita/Hariyama to do the whole thing again. Cycle through this a few times and you should be the winner.
There you go more information.