Hi thanks for contacting HCM.. Your father having smoking induce cancer growth in throat .... That malignant growth might spread to larynx and affected it ... So voice is affected.... Get your larynx examined by laryngoscopy ... If inflammation there steroid given ... If cancer metastasis suspected radiotherapy or chemotherapy needed according to type and extent of malignancy.... For bronchitis spirometry done to rule out severity and treatment accordingly... Bronchodilator might given.... Avoid smoking strickly otherwise condition deteriorate fast.... Consult physician for your case ... Take care