A person genuinely unable to cover may have a valid prayer under the relevant concession. That concession does not necessarily allow an unrestricted, clothed follower to pray behind that person.
This connects the earlier cases: valid individual prayer under an excuse does not always produce valid imamate for someone with full capacity.
Opening interactive controls...
Whom May One Follow in Prayer? Qualifications and Validity of Imamate
A person genuinely unable to cover may have a valid prayer under the relevant concession. That concession does not necessarily allow an unrestricted, clothed follower to pray behind that person.
This connects the earlier cases: valid individual prayer under an excuse does not always produce valid imamate for someone with full capacity.