How HIV affect the immune system?

HIV weakens a person's immune system, making it more and more difficult to fight disease. This effect is called AIDS (Acquired Immune Deficiency Syndrome).

HIV attacks a cell in the body know as the T cell or CD4 helper cell. When HIV destroys the T cell it makes the body harder to fight off infections making minor infections stronger/severe than ordinary.

Explanation:

the father in the first generation probably had the recessive colorblind trait in his x chromosome. if he and his wife both had the colorblind trait, even if she had 1 recessive and 1 dominant, then that trait would be passed on to their kids.

(since you didn't attach the family tree this is just an assumption)