He was 45lbs.
But he's at the bottom of the water tank. Alys couldn't reach him before he sank.
Plus, Biggs and Torrim were passing out due to the heat, so you had to teleport out of the chamber ASAP.
:(
Torrim's going to learn from his example and realise that not all members of a species are the same. That's why his Charisma's going up by 1 when he levels - because he's lightened up a bit. Also, his Swim and Use Rope skills are increasing, because of all the shit he's had to go through.