Have the rules changed recently? In the past, there has been no difference between a "medical" redshirt and "traditional" redshirt.
Some players have been granted 2 years when 1) the injury is severe enough to impact 2 seasons, and 2) the player has no relationship to UConn. But the vast majority of players only get 1 year to redshirt. Most use it their first year.
Whatever you want to call the redshirt, he's eligible to use it this year because he played in 3 or fewer games. An ACL injury wouldn't preclude him from playing all of next year too (and he still goes to UConn), so the NCAA is not likely to grant him an additional year (6 total).
After this season/school year, he'll have 4 years left to play 4 seasons.