Halc believes that if he (as the traveling twin) is stationary in some specific inertial frame of reference, he is free to adopt multiple answers to the question "How old is my home twin (she) RIGHT NOW?". That is incorrect ... there is only ONE correct answer to that question, for ANYONE stationary in the GIVEN inertial frame. That single correct answer is, "Whatever the person (he), stationary in THIS inertial frame, who is currently momentarily colocated with her, says her current age is". To understand the above last sentence, some elaboration is necessary. In that specific inertial frame of reference, any and all light pulses are guaranteed to be moving at 186,000 miles per second, relative to that frame ... that is the fundamental assumption of Special Relativity. If that light pulse is NOT moving at 186,000 miles per second, then Special Relativity is incorrect. Let's assume that Special Relativity IS correct. The people who are stationary in the above specific inertial reference frame have established an array of clocks, stationary wrt the frame, that are all synchronized with each other. And the adjacent clocks are separated by a fixed, constant distance ... for example, by a yardstick. Those people have accomplished that synchronization by using their knowledge of the separation between the clocks, and by their knowledge of the speed of a light pulse in their frame. When someone (say, Tom), stationary in that inertial frame, asks "How old is the home twin (she) RIGHT NOW?", the answer is "She is whatever age the person, named Steve, who is stationary in our inertial frame, and who is at this instant currently momentarily colocated with her, says she is. Now, Halc, who is also stationary in the given inertial frame, says that "No, she can be lots of different ages right now: different inertial observers, who are moving wrt one another, give different answers to that question". Halc is right to say that inertial observers (in inertial frames moving wrt the given inertial frame) will disagree with those of us in the given inertial frame. But Halc is WRONG to insist that people stationary in our particular inertial frame aren't required to accept Steve's answer to the question. People stationary in our particular inertial frame MUST agree with Steve ... otherwise, they are REJECTING the fact that the speed of light is 186,000 miles per second in our inertial frame. And rejecting that fact is rejecting Special Relativity itself.