(Translation: My love, may Allah preserve you; my heart, may Allah give you health/security from illness & grief.)
It's a really great way to remind ourselves as parents that Allah is the One Who can make our kids better; & taking advantage of a parent's accepted du'a as well. It's far better than fawning over our kids with hollow words that may or may not be true.
Rather, they would always make du'a for them: "Allah yesleh7aalhum" - may Allah correct their affairs, and even acknowledge that perhaps they were emotionally blind to something which was in fact a source of khayr.
Though they obviously experienced many emotions with regards to their children, they had the presence of mind to step away and understand that their view of the matter was not the only one or even the right one; they always turned back to Allah and prayed that whatever their child's Qadr was, it was one of good and guidance.