.
The money was gone because of Potters crime.
George never trusted Potter. Potters theft would not upset George as much as his uncle’s negligence. If you see again you will see that George was really really angry with his uncle who was the one who let George down. He actually let George down first by being so irresponsible he wasn’t next in line to run business. If he wasn’t negligent and irresponsible George would have been able to leave.