I think there are various possible explanations for his behaviour, from purely innocent (but thoughtless) to really creepy.
My advice for you: Do not agonise about it! You cannot look inside his head, but you can take action yourself and gain more control over the situation.
About the PC and working from your room instead of the lab
Ask him why he does not want you to use the lab PC and why you should work from your room. You could introduce that question by telling him you wonder about the changed rule/policy. Does he have a reasonable answer?
- Yes > Good, then do so.
- No > Then tell him, you see no reason in why not to use this PC in the lab and you will continue using it.
About unwanted video calls
If he wants to video-call you at a time or in a situation you are not comfortable with, just deny it and offer a phone call, a written chat or ask him to delay the video call. There is no need for you to justify! Just say, you prefer another time or a different way of communication now.
In contrast to some other posts, I do not recommend making excuses (broken camera or so) and hoping he gets the hint, for several reasons:
- Some people are really bad in getting subtle messages. They are not mean or stupid, they just lack this skill. If he belongs to that group, your situation does not change.
- You might feel uncomfortable with lying, even if it is a white lie. So, you would exchange one bad feeling with another. (And if he sees you video-chatting with someone else, you will need to explain things - another unwanted situation.)
- If he really is creepy, he might realise that his actions affect you and he might enjoy having power over you. That is the opposite of what you would want!
Thus, no excuses, but a polite refusal.
About working and calling late at night
Well, working at night is common within academia. However, make sure you are the one to decide if a night shift is necessary. Furthermore, make sure you get the corresponding rest periods as well.
One final remark
Since you mentioned possible cultural differences, I assume you have a different cultural background than your adviser. If this is the case, you could try to talk to someone from his culture and ask how to bring up the above mentioned issues to him in a way that is both clear and polite in his culture.