Pulmonary tuberculosis spreads by droplet infection, other type of tuberculosis not infective,  You have to cautious if the case is sputum positive case, also enquire whether he is treatment or not, TB needs prolonged treatment and more personal hygiene.

Tuberculosis is spread by droplet infection through coughing etc if the germ is present in the sputum, which is open TB. Other cases are closed and not infective. If a person suffering from open TB takes anti tubercular drugs for 14 days within a 6 to 9 months therapy which includes Rifampicin then he should become closed or non-infective. We are talking about lung TB. Glandular TB doesn't spread in the same way. Most indians, including you perhaps may harbor a ghons focus which is a latent TB infection in the lung hilar lymph nodes which is usually calcified and may or may not become active during one's lifetime depending on the status of immunity of the person. BCG vaccination may offer some resistance against TB infection.

Hello if it’s a close TB case then there is nothing to worry but please ask your friend to wear mask while coughing

Only if it's present in his sputum.