It is not allowable for a Muslim to keep apart from his brother for more than three days, for one who does so and dies will enter Hell.

[Abu Dawud 41.4896]

It is not right for a Muslim to remain apart from his Muslim brother for more than three days . When he meets him, he should offer him salam thrice and if, the other does not reply, the other takes the burden of the sin.

[Abu Dawud 41.4895]