What should we do about the husband's brother who is jealous of my husband to the extent of insulting him and refusing to attend joint gatherings, especially after my husband imported goods different from his and achieved success with them?

A Muslim must love for his brother what he loves for himself, especially if it is a brotherhood of faith and kinship.

Envy and hatred are diseases that corrupt religion and sever ties of kinship.

Nothing expels the evils of souls and removes their grudges like showing kindness to them. The Almighty said: (Nor can a good deed and a bad deed be equal. Repel [evil] with what is better) Fussilat/34.

If someone wrongs you, repel him with kindness, for that will turn enmity into love.

Whoever perseveres in showing kindness to those who wrong him will achieve great happiness in this world and the hereafter, and whoever seeks refuge in Allah from the whispers of Satan, Allah will protect him from it.

Whoever shows kindness to his relatives who cut him off, and he treats them well while they treat him badly, it is as if he is feeding them hot ashes as a recompense for their wrongdoing, and he will always have a helper and supporter from Allah against them.

The husband must fear Allah regarding his brother and avoid harming him as much as possible, and strive to show kindness to him and not respond to evil with evil.