My friend was recently diagnosed with leukemia,he never knew he had it ,the doctors took blood?

tests thats when they told him that he had this disease,i asked him if his gums bled,thats a tell tale sign of leukemia.his white blood cell count was extremely high,hes taking chemo treatments,and going for blood transfusions,can anyone tell me is it possible for a person to be symptom free with leukemia? i just made friends with this gent we were going to make plans to meet each other,i feel very bad about this.i meet a guy via the phone and this happens.