In addition to the proteins (agglutinogens) existing on your red blood cells, other genes make proteins called agglutinins (a-GLOO-tin-ins) that circulate in your blood plasma. Agglutinins are responsible for ensuring that only the blood cells of your blood type exist in your body.
Older children and teens are unlikely to start calling a stepmom mom or mother partly because of their fear of disloyalty to their biological mom. It is vital for all parties involved -- biological parents and stepmom -- to support their child's choice of what to call the stepmom.
In most cases step parents incomes is not used. It may come into factor as far as living expenses etc but mom probably cannot get an increase just based on your income. You are not required to make his child support payments should he not be able too he would just go into arrears until he is got up. Also if he ever goes into arrears, a lien can be put on any housing owned by both of you and any joint bank accounts levied.