My boyfriend's. Wife just passed her son is staying. In the home that they bought he refus. To move out so my boyfriend. Can move back in what can we do

Who OWNS the house? Meaning whose name is on the deed to it.

It is up to the owner of the house, So whose name is on the deed? The owner of the proper (unless it is the child) can merely evict the person in the house.

Your post is intelligible. Please repost in full, complete sentences. Include your general locale as laws vary by area.

The only part that is understandable is that someone's son moved into a house and you want him out.

First: it is clear that it isn't your home.

I agree that the rest makes no sense. Worst interpretation is that your boyfriend's EX wife passed, and the house belonged to her by divorce decree.
That means that her closest kin, her son now owns the house unless there's a will saying otherwise.

If your boyfriend was still married to her, and there was no pending divorce, then he gets the house and can evict her son, as long as he is 18+.
If he isn't 18, Social Services has to take over, or relatives, etc, and they will determine when he leaves.

As near as I can make it out, the dead wife is survived by her husband and by her son. The dead wife and the OP's boyfriend owned the house together. The widower and the OP want the dead wife's son to leave, so that the widower and the OP can occupy the premises.

If the home was owned as a JTWROS (joint tenancy with right of survivorship), the BF can perhaps evict his step-son. On the other hand, if it was not (and this is more common), he would have to first establish his title by petitioning the probate court to probate his late wife's estate. Depending on the state or country in which the late wife lived, and on whether she left a will, her son may inherit a share of the property. But in any event, a probate case can take some time.


...
If your boyfriend was still married to her, and there was no pending divorce, then he gets the house. ...

Not necessarily so. It depends on the probate laws of the particular jurisdiction. There are a spousal elective share provisions, etc. to consider, but a probate court would have to figure it out.