Slightly OT but on Saturday a passenger with a short connection (in Y although he dropped his full size wheeled luggage above my CW seat) was making a bit of a fuss during the breakfast service asking to be seated further forward for landing. The CC politely explained several times that a) W, J and F were completely full and b) we were landing 30 minutes ahead of schedule so his connection wasn't that short.

To the OP, if there is a spare seat in CW then I'm sure the crew will consider a polite request to move your friend there and they will balance that with any other request for short connections. As you are Silver your friend can use business check-in, fast track and the lounge(s) as your guest. The new group system means that boarding together is a bit of a grey area and will be at the gate agents discretion. There is often someone checking for group numbers in the boarding area so you can just ask them which will not waste anyone's time.