A close work colleague has been seconded to a more senior position for the last year. He has performed excellently and the head of department wanted to keep them at the level for the next year so a new role was created and they went through the technicalities of applying and they were about to be interviewed this week. They suffer from a chronic illness which is classified as a disability but they managed the symptoms and up to the last month they have never taken sick leave for it. He ended up being signed off for a month (after months and months of massive amounts of stress as they were covering several roles at once by this point). He just came back this week.
A new manager started 6 weeks ago (the role reports to this manager) and has suddenly decided that she does not want to fill this post after all. The official reason she's given is that she may restructure the team but she has also told another colleague that she is worried about the candidates ability to do the job because of their illness. She hasn't spoken to the candidate about his illness at all and I don't know if she knows that the head of department had commitment to keeping my colleague at this level.
It's all a bit of a mess and I want to support my colleague- he's been working his arse off and it seems so unfair. Can HR do anything given that the manager hasn't admitted officially that her concerns are down to health? Can a private conversation be used as proof in these situations?