It appears that the cue needs a complete refinish, and a collar replacement not that big of a deal. I would recommend that if the joint collar is cracked, you should also replace the Butt collar so that the material is an exact match. I have done a number of Huebler Cue refinishes over the last few years, and with the current materials available it is almost impossible to match the collar material Huebler used.
As far as, the stress fracture in the cues butt, I would core that section an inch or so past the crack, and put a sleeve in the butt to reinforce that area. While the crack may still be visible to some extent, the cue will be structurally sound and the crack will move no further. In fact it most cases that area will be stronger than it was originally depending upon the core used in the bored out cavity.