So Falco doesn't leave Shou like he was planning? Why was he gonna leave in the first place? They are actually like a little family?? I just wish the best for them.
Falco was more concerned about her well being. Shou also gets along with the townspeople and has a life outside of hunting unlike Falco. I also think that it relates to Falco's experience with his mom when he was younger. Since his mom did not let him stay in towns, he did not get to experience a normal life, and he might have wanted that for Shou.
I have been reading the novel online. I posted the link a while ago, but you might have overlooked it.
https://ncode.syosetu.com/n6860dt/

Okay, so I am reading a MTL version of the novel, so this is all based on my comprehension of a bad translation.
Spoiler
Okay, so the festival starts and Shou surprises Falco with her attendance in the upcoming hunt as a healer's apprentice. It is supposed to last two months and Falco was keeping it a secret that he was leaving. So she makes him really happy when she says "You said that we will always be together, forever." as they are leaving on their trip. While they are out, she does a good job healing, and they return to town without anything bad happening. Leon decides to become a hunter again since he was healed, and they coincidentally meet up with his and Falco's ex girlfriends who happen to be a part of their old party. Both guys decided to stay away from the exes and to create a new party. Upon coming home from the hunting trip, it is beginning to be summer.
Shou finds out that her friend got in a slime accident earlier, and locked herself in her room due to her looks being destroyed. With the help of Alfie, Shou helps to heal Aura so that she goes back to normal.
Meanwhile, Falco is looking to buy a house so that Shou, Leon, and himself can live in it. This is found toward the end of summer according to the novel. Before they move into the new house, Lyra shows up. Lyra is Falco's mother, and from the sounds of things, they do not get along. They had one meal together at the inn, and Shou decided that she does not like this woman since she is not caring toward her own son, but does not mind using him to benefit herself.
Later, it becomes clear that Lyra was a hunter that took Falco with her everywhere, so he didn't have a stable home. She did not always feed him, or let him keep his earnings to buy things for himself. It was later revealed that Falco was abandoned the moment he turned 15, and he had to figure out how to function in town, and how to earn money. He didn't know about needing a guild card, or how to get jobs. All he knew was how to hunt.
Now, even as an adult, whenever he sees his mother, Falco goes back to feeling like a helpless 15 year old kid who can't do anything. Shou learns a little bit about Falco's history from Gina, but she does not push to know more, and is waiting for Falco to explain for himself. So all that she can do is support him by staying with him and being herself.