Actually, I have no idea.
I'm just writing
I love that song YOU'LL BE IN MY HEART YES YOU'LL BE IN MY HEART FROM THIS DAY ON NOW AND FOREVER MORE
Whenever there's a sad song, there's always a damn sad ending.
I actually have a story like that on Quotev. It's called AoT Parent Scenarios. It's where the AoT characters find children and raise them