Care and Feeding She’s very helpful, but at what cost? Photo illustration by Slate. Photo by djedzura/Getty Images Plus.  Care and Feeding is Slate’s parenting advice column.  Have a question for Care and Feeding?  Submit it here . Dear Care and Feeding,  My husband and I have two kids, “Leah,” 4, and “Wyatt,” 6. Lately, Leah has become quite the little tattletale and eagerly runs to get her dad or me whenever Wyatt is about to do something that is against the rules. For instance, she came by and got my husband the other day to say her brother was climbing the floor-to-ceiling bookshelves in our family room.…