Baseline observe. You're beside him for everything. Watch where he pauses and where he flows, that's your data. No pressure on him or you to go solo yet.
He drives 5 minutes. Pick one step in Together 1 and hand it to him: "you read that bit to me." Note whether he needs prompting to start.
If he shuts down or gets sharp, drop a rung without comment. Don't name it. Just step back in. Collapse is information, not failure.
These are the quiet notes you saved inside each lesson. Together they are your picture of where he actually is, which sets the level for the next nine weeks.
If you need to reset Talan's progress on this device (e.g. starting fresh after testing):