Hi, K.! Speaking of the Bumbo, something that's newer (and, I think, better and more stylish) is the BeBe Pod Plus. It's the same idea- helps the baby sit up, but it has a tray, two placemats and a sassy toy attachment. My 4-month-old loves hers!
Also, something that my friends did at my shower was that they gave me a library of baby books. A great idea for my curious new daughter AND my 6-year-old son (also Nicholas) who loves to read to her! If your friend's older child can "read" (hold a book and make up a story), it's a wonderful gift idea and great way to help big brother feel involved. And of course, gifts for a tired two-time mom are always appreciated- think massages, salon certificates and "gift certificates" for babysitting or meals when the new baby comes along. Good luck!