The short answer is "yes", the sibling living in the house can be forced to move. The longer answer is "but it might take some time & effort." You might very well need to bring what is called a "partition action" to force the sale of the house (because both siblings are co-owners, neither of them is a renter, so a simple eviction won't work).
You'll probably need a real estate lawyer to assist you with this.
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If both siblings agree to sell, then they both need to understand that in order to sell the house some improvements may be needed and the house needs to show nicely. If the one living in the house can keep it neat and clean so that is shows well, then why do they need to move yet? On the other hand, it may be unfair for one to benefit from the use of the house until it is sold. You may need to reason with the one living in the house or come up with an agreement for them to stay.
The beneficiary living in the house can be forced to move out, but you must consider the costs involved, the time involved, as well as the family relationship which may be destroyed as a result of forcing them out, especially since they took care of mother for so long. Did they receive any compensation for taking care of Mom? You must also consider the cost of insuring a vacant house - many insurance companies do not like to insure a house with nobody living in it, so it is very expensive.