The Scrum Master should talk to the IT manager and explain that progress in Scrum comes from inspecting an Increment at the Sprint Review. This is because:
The Scrum Team is self-managing and does not need to report to anyone outside the team1.
The Sprint Review is an event where the Scrum Team and the stakeholders collaborate on the product and inspect the Increment2.
The Increment is a concrete and usable outcome of the Sprint that provides a measure of progress and value delivery3.
The IT manager can attend the Sprint Review as a stakeholder and provide feedback on the product and the process4.
Reference:
Scrum Guide, page 7, section "The Scrum Team"
Scrum Guide, page 13, section "Sprint Review"
Scrum Guide, page 10, section "Increment"
Scrum Guide, page 14, section "Sprint Review"