They do have their somber moments, but it's brief and doesn't really do much in terms of establishing their bond over lost loved ones. They keep cracking jokes and pop culture references instead of holding conversations that would could've added depth or provide a much more organic build-up to trusting and accompanying Raya - a lone wanderer. But sadly, they were more concerned over the number of characters they could shove into the film than they were with actually developing said characters into actual people. Now the plot's lack of originality would've been fine if they had a strong cast and some solid writing to build upon. The movie's basically another allegory on greed and how it can tear humanity apart. Even if it were, there's nothing to suggest that they would follow the customs of that area as it is today. Though this would, of course, assume that Kumandra is in what is known today as South East Asia. So Raya would call Tong "Uncle Tong", Boun would call Raya "Sister Raya", and Raya would address deity-ish Sisu as "Master Sisu" or "Lady Sisu". In Asian cultures usually you would address people using familial relationship: you would call a person who is around your age or slightly older than you with "brother/sister", person who is in the range of your parent's age with "uncle/auntie", person who is older than that with "grandpa/granny", and revered/high status/deity figure with something like "master/lord/lady". In South East Asian cultures in particular and Asian cultures in general, it's considered very rude to address people who are older or in higher status than you with only their names, such as when Raya calls Tong or Boun calls Raya or Raya calls Sisu (a deity-like figure) with their names only.