There has been a restructuring where I work and our Team is now led by a guy who used to supervise two Teams. Until very recently he mostly took care of the other Team's activity so, he knows very little about what our Team is doing.
Since he has to lead a single Team, the management told him to spend at least 30% time on development tasks. While the guy is handling legacy projects and L3-support tasks quite well, he requires constant help on getting anything done on our project. My estimation is that the Team spends about half an hour to help or fix his code for each hour he works.
Our Sprint has a few story points for handling incidents (also for some satellite apps), (optionally) a few story points to handle a non-functional requirement story (e.g. fixing some big tech debt, performance optimization). All the rest goes to handling stories required by the internal client.
The Team is very small, but we managed to have a pretty stable velocity. However, due to Team members spending a significant time helping the Team Leader with his tasks, the Team is not visibly performing better despite being a little bit bigger.
I am wondering about how to formally indicate inside the sprint that Team members can commit less because they need to help the newest member.
One way would be to increase the story points for the stories assigned to the newest member so that the effort reflects the reality (extra time spent on solving it) and take a little less for the other stories. However, this might make the PO wonder why the same Team members can commit less individual work.
If the newest member had been a Junior (as opposed to being a Senior Dev promoted to Team Lead), it would have been easy, because any sane person understands that junior members require help and mentoring.