I enjoyed the warmth of this story! It's a simple tale of love and family, with the quintessential characters - the teenagers, the protective Dad, the understanding Mom. I like the surprise of whose smile it was that did the trick. I thought it would be one of the parents who smiled. The Mom refers to the girl's smile while talking to her husband, but not the boy's. Maybe you could add a line of dialogue there ... ?
While I didn't find 'errors' exactly, I did find some amount of redundant 'telling' and a few adverbs that could perhaps be edited out. If you do work on this one again and agree with this, send me the link once you're done and I'll rate it higher!
A heads-up: You have the word 'killed' in there, needing an ASR rating.