Hi Lebohang,
Please find the attached OML as per your requirements. I did the below changes -
1. Set the Illness container name as "IllnessContainer".
2. Added style = "display:none;" attribute in "IllnessContainer".
3. Create on change event for Leave Type dropdown with LeaveTypeId input parameter.
4. On Leave Type dropdown change event display and hide the "IllnessContainer" using javascript.
Thanks
Vinod