Birth Family- Would you want to know if you were never told?

Question For Everyone... But got to tell the Story First... My Father's Birth Mother Never told Her Husband or her 2 Daughters about my Dad Before she passed away 30 years ago. She was engaged to be Married to a man in Texas. When he was sent off to boot camp She came to Oregon to Stay with her Brother In Portland. She had a affair and got pregnant. Her fiance was begging her to come home but she made up excuses. When she Could no long hide her Pregnancy She Ran 2 hours away to Eugene, Oregon. Her Brother filed a missing Persons Report. He didn't hear from Her for over 3 months. When she Called to ask Him to pick her up from the Hospital since they wouldn't let her leave unless she had a ride. She moved back to Texas and was Married with in a month. Her Brother took her secret to his grave as well. His wife didn't want to carry it with her and she told their Children. But they lost contact with that side of the family after Her Death. My Question is (3 parts): . If you were the sister's would you want to know you had a Brother after all this time? Would it Change the Respect you had for your Mother to know how unfaithfulness and deceitful she was? Would you be Look at the Adoptee as a reminder of that unfaithfulness and Dark past?