Im looking for a martial arts manhwa where mc was sickly and his brother was the opposite ...

Im looking for a martial arts manhwa where mc was sickly and his brother was the opposite and went off to learn martial arts. The sickly mc was at home with his parents, helping out at the store or restaurant i think? The rest is sorta fuzzy, but i remember a painting being involved with his growth and an old man that introduced that painting. It was a old classic black and white ink painting, this is as much as i can remember. Please help