A. Yes, it is possible for some people's social security benefits increase after age 70 if you keep working after that age, here is the reason -
Social security benefits are calculated by adding your highest 35 years of wages and divide by 420. This gives you the Average Indexed Monthly Earnings (AIME). The Social Security Administration applies a formula to the AIME to determine your full benefits amount at your full retirement age.
For the years you had no income (especially for many immigrants who have short work life in the U.S.), your wages for those years will be counted as $0, so if you keep working to get more wage-earning years towards the 35-year count, your AIME will increase, so will be your social security benefits.