so my response is limited to the limits that your question you posed. If I had more context I could give or more contexted answer. If you would like to give more information I can give a more specific response. I will however provide an answer within what you placed so far. If you choose to share more about your situation you can consider the following questions: Are you being physically abused? Are you being verbally abused, such as insulted? Is the person simply very emotional, and is not really involving you into it?
So Tyler, my real answer is dependent on the context. In some situations in my life, I had to draw lines and point out to the person what they are doing. In other situations, I could not point out to the person because we did not have a developed relationship where I can do so. One context is the work place with your boss and you are dependent on the job for money. Because we need money, we don't always have the liberty to share ourselves. But, here is the other interesting point. If you have been walking the desteni process for a while, you would have seen how we are responsible for our own reactions. Thus if you do choose to support another and point out an abuse they are doing, that decision can only realistically come after you have stabilized yourself. Because if you are not stable and you choose to support then you are not really supporting.
Another dimension is that if you choose to speak to the person that you are going to need to take responsibility for yourself and what the results are. And this is a self-honesty point about whether you do indeed see that the person is reacting, and you do indeed see how you can best support them, and by speaking to them you are doing so in a way that is best for all, which includes you.
You did mention that you are FORCED to spend time with the person. In a situation where I am indeed forced too, it logical that I maintain peace in the situation. At the same time I need to ensure what is best for all. The strength and development of your own being is what you ultimately need, which you can only developed over a long period of time through walking your mind and bringing back pieces of your real self, which you can do so through living words.
Basically, what you should do is dependent on the situation. And here I am referring to where you are in your process. If you are more developed in your process and so your stand in who you are, living words of self-responsibility and self-honesty for example, then you will see more clearly what to do. But if you are not so far in your process, the best this is to work on your own reactions with the person and continue developing your self-responsibility and self-honesty, and so self-awareness. This is how I walked my process. You will find that people who react, are in a way your greatest teachers, because all they are doing is revealing your own reactions. Our absolute potential would be that we could stand completely still in the face of any person's reactions. Not that that would be best for all behavior, but that is our stance within who we are.
So if you want a challenge in your process, you can see whether you can learn something from this person, by seeing where they are revealing any reactions within you and be grateful for that. Now, obviously there is the point where they could be abusing you. You haven't provided me with enough information to be able to say that, or give any specific advice, like if someone was hurting your body. So this is where your self-honesty comes in. You can provide such details if you like, however I do advise to do self-forgiveness and ensure your self-stability so that you don't twist the information so that it becomes an opinion or idea about the person that is not true. Again, that is your self-honesty.
Ultimately, the best advice for any situation where you have the decision about what to do, is to stabilize oneself with self-forgiveness, understand the situation by writing it out, doing further self-forgiveness on any judgments and emotions which are clouding and create lies, and to then what is physical practical and best for all involved. We each create our lives with the decisions we make. So how we come to our decisions, determines our futures.
I wish you the best, and may you create the best outcome possible.