(1) Although I haven't seen him for years, I still remember how he looked from when he was younger.
(2) Although I haven't seen him for years, I still remember how he looked from the time he was younger.
(3) Although I haven't seen him for years, I still remember how he looked when he was younger.
(4) Although I haven't seen him for years, I still remember his younger face.
Which sentence is correct?