Hi, welcome to HCM.
Unfortunately there is advanced cancer at this stage. Blood in sputum may be due to different reasons. It may be due to chemotherapy
induced severe gastritis
. Another reason is that any erosion of bronchus
by lung malignancy.
Considering patients conditions andseverity of symptoms you need to consult your physician. If there is continous blood then few more investigations may be necessary. It depends on clinical examination.
Hope I have answered your query.