It is heavily disputed whether or not Weed Bro's Father is the true father of Sarcastic Bro. They do not share the same family name, and they look drastically different, unlike the resemblance between Weed Bro and Weed Bro's Father. It is likely Sarcastic Bro has become accustomed to a life of sarcasm due to hardships living in a divorced home. It is likely, as Weed Bro's Mother is human rather than a stick-figure, that Weed Bro's Mother is also Sarcastic Bro's mother, and Weed Bro's Father is his stepfather, making Weed Bro Sarcastic Bro's half-brother.
Sarcastic Bro's Father, though never seen, is likely to resemble Sarcastic Bro. It is possible that Weed Bro's Mother married Weed Bro's Father after divorcing Sarcastic Bro's Father. Whether or not Sarcastic Auntie is Sarcastic Bro's biological paternal aunt, step paternal aunt, or maternal aunt, is unknown.