There is a way but it cost money If you get a playstation 4 controller and use this app called ReWASD, you would be able to map the leftstick to left and right, then map the left stick to your mouse.
The sensitivity aint the same but I was able to beat the game like this.
imo the keyboard controls are good (at least for those of us, whose both up down buttons size is equal to single left or right button)... but i prefer play fps via gamepad and also has like 1000h in DS1 so my opinion in not really..
