Assuming everyone on the deed signed the sales contract, the survivors and/or the dead guy's estate representative have to close. If closing is delayed, your cost of living in a hotel/renting storage space/paying to move the second time all come out of sellers' money. Have your attorney write them a letter IMMEDIATELY telling them when mom's current housing goes away & saying that she'll sue them for breach of contract & delayed closing damages if they don't close "in a timely fashion".
If daughter has taken the entire property via joint ownership, she can complete the sale without needing any authorization from a court. It's now hers, free & clear. If she & parent were joint tenants, then she owns 1/2 & the parent's estate owns the other 1/2. The estate representative will probably need an emergency order from a court allowing him/her to complete the sale within the next week. Usually it takes a few days to get a representative appointed. The parent's executor/representative will have to jump on the stick & get into court fast.
Whether the parent had a will or not is irrelevant. The sales contract survives his death (unless it specifically says otherwise). It is considered a 'debt' the representative must discharge. If closing is delayed, you sue the estate & the heirs lose whatever $$ you are awarded. This is their incentive to close quickly.
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This is not legal advice and you are not my client. Double check everything with your own attorney and your state's laws.