The best thing to do is ask why they are doing it this way now. There is no obvious benefit to the company. One factor might be the following, although it doesn't really fit the case. On the plus side, if he has wages, he could still contribute to an IRA.
According to the IRS:
"If you retired on disability, you must include in income any disability pension you receive under a plan that is paid for by your employer. You must report your taxable disability payments as wages on line 1 of Form 1040 or 1040-SR until you reach minimum retirement age. Minimum retirement age is generally the age at which you can first receive a pension or annuity if you aren’t disabled."
