Oh, it definitely makes sense to have heart-warming scenes with horror. I have that a lot in my horror stories.
Because often enough, it gives those characters more depth. We see how they are when they're not afraid, how they are when they're with the people they love most in the world. It brings more to the table than "the poor sap who got stuck into this mess"
Even more, it brings characters the determination to fight back. They have something, someone, to protect from the horrors, and dangit, they're gonna try their best to make sure it happens.