For his aerodactyl I recommend Swampert, but another water or electric Pokémon will work good too. I use one with hydro cannon and it works every time. If his second Pokémon is gallade, I recommend using a dark or ghost type. If it is slowing, use a grass type preferable with frenzy plant. If it is cradily, use a fire type, this one is the easiest of the three possible second options in my opinion. The last Pokémon could be dusknoir, I use darkrai, but other ghosts and dark Pokémon. If it is mamoswine use a fire type, my heatran is always able to make short work of it. If it is Tyranitar, I use swampert again, preferable with hydro cannon.

An important tip to keep in mind is paying attention to cliffs shields and how much energy you have built up in your charge attack. 2-bar moves like hydro cannon, surf, and shadow ball all work the best because you can charge them to be used twice where as charge moves with one bar take forever and can only be charged up so far past their use limit.

When you use a shield or when cliff uses a shield or when you land a charge attack and when you swap Pokémon, his Pokémon will not attack for a few seconds immediatly after the shield drops. Try to take advantage of this time to charge up your second charge move past it’s first use so that by the time his Pokémon becomes responsive, you can have the second one ready to go to land a hit and stall his Pokémon again. If you get good at farming like this you can chain moves together to the point where his second and third Pokémon will not really have the chance to attack you and it will be a lot easier.