Ill -health retirement- process / how long

[Silverblue]

Hello,

Other half has been off sick for over two years. First physical, then mental health reasons. Manager suggested going for ll-health retirement. Not heard from OH in over a month - can someone shine a light on how the process works and how long it might take? He is on the payment from the pension which will be scrapped next year so need to financially plan. Obviously I understand there is a chance he won’t get ill-health anyway.

Thank you!