1) Linus is a perfectionist
Thaddeus is a little careless
2) Linus is quite uptight
Thaddeus is more laid back and maybe naive
3) Linus cares about his brother
Thaddeus is quite immature
4) Linus disregards his brother's feelings
Thaddeus has a sense of self-identity
5) Linus has a sense of affection for his little brother
Thaddeus is a typical little brother