Hi My Father Is Suffering From TB And This Disease

hi my father is suffering from TB and this disease attacked him second time, 1st time he had completed the treatment and had clear reports, but it came again, now he has again taken the TB medicine for last almost 8 months, he always has been complaining gastric abdomen and for now its stopping him eating his meals properly even he cant take juices, he is taking rifampicin 150gm and isoniazid 75 mg tablets, levofloxacin 500mg and streptomycin sulphate igram injection daily,,
please guide what is his problem else of tb and what should we do for him..
i will be reallyyy grateful