My brother thinks my paintings are ugly. Could he be right?

Short answer
Yes, everyone is always right

Long answer
If your brother likes yellow sports cars but hates red tractors, he is, of course, right, but this only says something about him, it doesn’t say anything about either tractors or cars. The question you should ask yourself is whether it is important to you what your brother thinks. The answer is yes more often than you imagine, in which case you are faced with a choice: change brothers or change your art.

Question # 45 from “What is art” (must buy) by Ernst Billgren