A.T. Robertson Commentary Luke 15:14

"And when he had spent all, there arose a mighty famine in that country; and he began to be in want." — Luke 15:14 (ASV)

When he had spent (δαπανησαντος αυτου). Genitive absolute. The verb is here used in a bad sense as in Jas 4:3. See on δαπανηLuke 14:28.

He (αυτος). Emphasis.

To be in want (υστερεισθα). The verb is from υστερος, behind or later (comparative). We use "fall behind" (Vincent) of one in straitened circumstances. Plummer notes the coincidences of Providence. The very land was in a famine when the boy had spent all.