Delaying Payment Until End of LTD Eligibility

[401 Chaos]

Any thoughts on possible ways to work the following scenario:

Company has long-time employee who has history of going out on disability (STD and LTD) and returning to work. Employee is about to go out on LTD again. Company likes the individual (sympathetic disability issues) but is tired of the back and forth and would like to terminate individual's employment. Company would give individual "severance" amount equal to 6 months salary in exchange for termination and signing a release, etc. Problem is that the severance payment would offset amounts to be paid under the LTD plan so company would like to delay that payment until individual's eligibility for LTD stops. Problem is there is no way to predict when the individual will no longer be eligible for disability. Plan provides coverage up to age 65 if disability continues. In the past, the individual was only on LTD for a few months and that is likely to happen again but there are no guarantees of that so it's theoretically possible (although very unlikely) that the payment could be delayed for a number of years--well past S-TD exemption and separation pay plan exemption requiring payment by end of second year following year of separation. I'm not seeing a clear way to exempt this or make this comply with 409A. Thanks.