Shouldn't be be limping and\or walking with a cane since his LEFT leg is messed up?
But he is walking as if there is nothing wrong. (Last panel his leg is rolled up when it was down the whole time)
@Koremitsu_Arita they are amazed because a refrigerator is a giant box that weighs 150-200 pounds. Normally delivery people would use special equipment to move it upstairs.
@Eclipse01 they knew he was a cripple before he even lifted the refrigerator. He's wearing long pants too. If he was stumbling or something, it could mean anything. They just called him a cripple like they knew him personally.