Animations are blendable. I don't know if this is universal, or requires some hardcoded element, but you could test it.
You'd need to create it as a new animation (going the name hack route is the easiest way to do it) and then you just set the animroot to the base of where you want to affect the model. In your case, you'd set the animroot to torso_g (or maybe torsoUpr_g). Then the legs should inherit the animation from the idle animation - i.e. be standing.
Of course there would be an issue with the right arm posed to be resting on the right leg, but one problem at a time.
Edit: So I played around with it a bit, since I was already hacking animations for one of my own projects. I took the animloop2 anim and removed the keys for the pelvis/legs and the position keys for the rootdummy. I replaced the keys for the right arm/hand/fingers with keys from the pause1 anim (with a doubling of keys required, since that anim is half the length). That gets you in the ballpark, although he still has a drinking problem, now apparently even further exacerbated.
I'll have a look at the TSL drinking anim, as I think they fixed that up. I know they properly aligned the glass, which is not the case in K1 (which doesn't actually use a glass, but if you add one it's positioned poorly and the fingers clip through it).