K.R.
If she doesn't already have one, I'd suggest a Moby Wrap or other type of "hands-free" baby carrier. (Not a sling, because Mom usually feels that she must still keep a hand on the baby.) With the carrier, she can meet baby's need to be held and close, and still have 2 hands free to tend to her older child. Great for trips to the playground, store, etc. as well as around home!