Is the young man's position considered correct after he withdrew his marriage proposal, then returned to express his desire to find a suitable job to please his father, and then became engaged to another girl?

You must believe that everything happens according to Allah Almighty's decree. Perhaps this young man's withdrawal is better for you, as Allah Almighty says: "And perhaps you hate a thing and it is good for you." Therefore, do not cling to this young man, and turn to Allah to compensate you with someone better than him. Legally, the young man has the right to withdraw from proposing, especially after your father rejected him.