TETRALOGY OF FALLOT
If your son is having a lot of cyanosis and very symptomatic of tet which are severe cyanosis and problem breathing, operation for uncomplicated cases are done after 3-4 months of age and mortality rate is only less than 3percent.
If untreated 55 percent grow up to 10 years old. So , there's hope for your son. Please ask your cardiologist.Good luck!