Any Pokemon properly trained can defeat Red. Try this Weavile moveset.
Ice Punch: Deal with Venusaur. STAB. Weavile has a good attack stat. High accuracy, decent power.
Brick Break: Used for Lapras and Snorlax. Breaks through light screan and reflect. High accuracy, decent power. Attack stat.
Dig: Deal with Pikachu. Good damage, high accuracy, used to dodge attacks. Attack Stat.
Surf or Night Slash: Surf can be used to take on Charizard. However, since Weavile's Sp. Attack is not that great, you might want a move that gets STAB, so Night Slash.
