Gallbladder and bile duct stone.

Patient age :70. As per his MRI and CT  report there seems to be stone in gallbladder and bile duct.  He is also having jaudice with high  biliburin and high alkaline phosphatase. Report: Gall bladder is well distended and shows multiple T2 hypointense signal voids in the gall bladder lumen average size 13 – 14 mm suggestive of cholelithiasis. Ill defined T2W hypointensity is seen in the GB lumen - likely sludge.  CBD is dilated measuring 20 mm in its maximum diameter with upstream bilobar IHBR dilatation, Two calculi are seen in the distal CBD, one just above the ampulla of vater. The other calculus in distal CBD measures 17 (CC) x 10 (TR) x 12 (AP) mm.  Cystic duct is dilated measuring 12 mm and shows sludge within. As per my understanding bile duct stone can be removed through ERCP and also gallbladder can be removed through surgery.  Can patient go for only ERCP?  please suggest in what cases gallbladder to be removed?