Sureerat Chiwarak sat with calm resolve in front of a Bangkok court as her head was shaved in a protest to support her activist son, jailed for weeks without bail on criminal charges of insulting Thailand's powerful king.

It was a moment the 51-year-old business consultant had never foreseen, but she felt desperate to do something after her son, student protest leader Parit "Penguin" Chiwarak, 22, was taken to a hospital after nearly eight weeks of hunger strike.

"My son is dying and I can't do anything about it. It's a terrible feeling. The people in power are letting my son die," Sureerat said in an interview.