Is it considered "takhbeeb" for a young man to agree to marry a woman given her suffering and the injustice she experiences from her husband, and is there still good in her for him after more than 20 years have passed, and will he do good by her after her children have left?

It is not permissible for a man to speak with a married woman about marrying her, whether by insinuation or explicit declaration, because that is a forbidden act of incitement (takhbib), even if the woman is experiencing problems with her husband. If the woman is divorced and her 'iddah (waiting period) has ended, there is no objection to her marrying this suitor or anyone else. Whether the marriage holds goodness is part of the knowledge of the unseen. The husband must treat her well and fulfill her rights, including justice between her and his first wife.