Issy is not being cross about Old Mistlethwaite going to help the little babies and do all the things little babies is needing just because he is an Old Malfoy elf and is thinking more about the family than about the house. That is not being the proper house-elf way at all, but Issy will not be being cross because of all the little bitty things the babies might be wanting right now and Issy could be doing but she is not doing. She will just be dusting the nasty old potion-stained glassy and tubey things in Master Professor Snape's workroom and she will not even be dropping any even by accident because she is a good elf.
If every little thing is sparkling shiny clean Master Draco might have the babies coming to Lake Cottage, and Lake Cottage would be liking that very much. Every house is needing babies some time, with their little mouths that is needing wiping and their little hands that is getting very messy and their little tummies that is always needing more things cooking and mixing and their little breaths that is breathing houses alive.
If every little thing is sparkling shiny clean Master Draco might have the babies coming to Lake Cottage, and Lake Cottage would be liking that very much. Every house is needing babies some time, with their little mouths that is needing wiping and their little hands that is getting very messy and their little tummies that is always needing more things cooking and mixing and their little breaths that is breathing houses alive.