That's wonderful that you are supporting her in her decision to breastfeed! Knowing it's the absolute best food for your grandchild, it's worth making sure all is well.
It's perfectly normal for a BF'd infant to need to eat every 2 hours. The milk digest quickly, so important to nurse when the baby is hungry. It's difficult to judge exactly how much milk the baby is getting per feeding, but you can be reassured the baby is getting enough if you have good output (8 or more wet diapers per day and at least one BM) and the baby nurses until satisfied at each feeding, which could be anywhere fro 15-45 minutes per feeding. The baby should seem content after a feeding. Also, if the baby is gaining weight well, then no need to worry!
You can help mom by soothing the baby between feedings, helping her recognize the true signs of hunger versus just needing to be held/comforted. We need to remember every time a baby cries doesn't mean they are hungry. However babies do need to suck to relieve stress, and if the baby doesn't take a pacifier, then mom is fitting that bill.
If you both are still concerned, contact a lactation consultant, either at the hospital where she delivered, or independantly... or la leche is a great resource too and it's free. Her pediatrition should be able to reassure all of you that the baby is gaining weight well and there's no need to worry!
Congrats on your new little one!
Shelley Scotka
Certified Childbirth and Breastfeeding Educator
Certified Birth Doula