The drummer HAS to learn to lighten his touch. It will make him a better, more versatile drummer. Or, suggest ( demand ? ) that he use some kind of sound muffling device. There are these thin plastic rings that go on the drum skins that effectively cut down some of the volume. And he could stick a pillow or blanket or something in his bass drum to deaden that sound a bit. These may help, but the drummer has to learn a lighter touch. Your PA should be enough for a "garage band" type of application - it could do small clubs and bars too. Gotta get that drummer under control.