I think you might be confusing "guarantee issue", with waiving pre-existing conditions. Many companies, AFLAC included, will offer benefits with zero, or very reduced, underwriting questions.. thereby "guaranteeing" coverage. However, that does not mean pre-existing conditions are covered. Most have a 12/12 or 12/24 clause. Meaning.. if I have been diagnosed, treated ( and that includes just taking a prescription pill ), received medical advice, or had a medical condition where a prudent person would seek medical advice, during the 12 months before the new policies effective date. That condition will be excluded for the following 12 or 24 months. I can be covered for everything else.. just not that particular condition. So let's say I sign up for a short term disability plan that starts October 1st, and I'm currently taking one prescription for a condition for my heart. If, in the next 12 months, I go out for a disability due to my heart... I'm not covered. I could have a back injury, broken bone, diagnosed with cancer, etc.. all those would be covered.. just not for my heart.
As for cancer, most cancer plans always have a question relating to current, or in the last 5 to 7 years, been diagnosed or received treatment for cancer. I'm 99.9 % sure, your employee would not qualify. However, I do not work specifically with AFLAC.. so contact them directly.
21+ years in surance/group benefits