UK: The employee described himself as 'medically retired' and has been on 75% pay since 2008 under the terms of an IBM health plan. The arrangement will finish

UK: The employee described himself as 'medically retired' and has been on 75% pay since 2008 under the terms of an IBM health plan. The arrangement will finish when the employee reaches 65. I'm sort of wondering if his pension contributions are based on 75% or 100% of pay scale. This kind of arrangement is not by any means normal in UK, and I wonder if the plan is still available to new employees. Most companies and public sector employers have a sickness policy that pays full wages for some months then declines steadily until employment is terminated, around a year in the case of my former employer.