Pippin was proud of his sons, though they were on a path he would never have chosen for them. He worried, and was afraid for them, because though they were in many ways more like their Rohirrim cousins than their own brothers, they were still Hobbits.
He had hoped his children would never know war, but he knew there was no point in talking the boys out of being soldiers. They were as stubborn as their mother.
So he smiled proudly as Bori pledged his oath to Aragorn, and Ari to Éomer, and silently prayed for many years of peace.