My daughter is a high risk pregnancy. May I ask questions here about her, such as, what is her risk of an abnormal baby at 40?

Half empty/half full. Your concern is certainly common when a woman has a high risk pregnancy but the term is a bit overused.Every pregnancy has an underlying risk of about 4% of having an unexpected outcome.That includes all premature, birth injury.birth defect, neonatal infection, etc. That's why it is best to get good prenatal care. The age thing adds another 1%, but is that really too much ?
~1%. Most 40-year olds have ~1% risk for down syndrome baby. Other risks that increase with maternal age: c-section, infertility, miscarriage, preeclampsia, diabetes mellitus, abnormal fetal growth (too little or too much) and stillbirth. Still, the vast majority of 40-year olds will have healthy babies to take home.
YES,BUT. But a much better idea would be to ask these questions of her ob/gyn. He would have all the history of her specific problem. Part of giving a detailed answer would also be the physical exam and any testing. This obviously can not be done online. In person would be the best.