That's probably normal, depending upon what his salary is now. Unlike the original Virtual Families game, VF2 doesn't display fractional money amounts, so he would have to earn almost a full coin on a work cycle before you will see the bank amount change. When an adult's salary is low (e.g. less than 100), you may not see an increase in the bank balance until they have completed several work cycles. You will see the bank change much more often at the higher career levels.