I want my roommate's homeless/jobless boyfriend to leave our home after staying for nearly 2 weeks
Why does his staying with you bother you?
I hate it because he uses up all the food in the house and makes a mess
Although it is nice to help people out when they are in need, people who living together are expected to share responsibilities like bills and chores. It sounds like your roommate's boyfriend is taking advantage of your kindness, and you should talk to your roommate about what you expect from their boyfriend if he is going to stay.
I'm not callous, but he had worn out his welcome.
That's fine. He was in the wrong for taking advantage of your kindness.