Do daughters bear sin due to their brothers' estrangement from them, which has lasted for years, despite their attempts to reconcile, and the brothers' refusal of reconciliation efforts?

There is no sin upon the brother if his brother cuts him off without a reason, as long as the brother is keen on maintaining ties and giving gifts. By continuing to strive to connect with them and show them kindness, he will attain Allah’s support. As it is stated in the Hadith: "If you are as you say, then you are feeding them hot ashes, and you will continue to have a supporter from Allah against them as long as you persist in that." He should supplicate for them and perform legal Ruqyah. As for the delayed marriage of the daughters, its remedy lies in supplication and presenting them to suitable matches.