>>228745I work in tech, dont fall into his extortion, document everything in text apps or better audio messages, then report everything to HR, his boss and the upper managers.
Also you might want to leave that company, such toxic environments are not good for software developments, the extortion will get bigger and more demanding, meanwhile a workforce with such lack of ethics and cohesion will most likely fail to meet deadlines and you as a junior dev will be forced to do overwork and even possibly workplace bullying.
Also, as a rule of thumb avoid interships in tech, there is no need for interships in the industry and also you are doing free work for that company something that is immoral.