There is good information below. Families can be difficult when it comes time to divide or allocate the estate. Try getting a BPO (Broker's Professional Opinion) so you have an idea what the property is worth. If your husband is willing to pay fair market value, and can get financing for the same, the siblings might see the value in getting cash out for themselves. If the siblings are also interested in buying the property the highest bidder should win. You need a professional Realtor who has worked with similar situations.
1. Who has rights to the property? Do the siblings and he have decision making power over the property together?
2. Can your husband qualify to purchase the house from a financing standpoint?
3. Is your husband prepared to take on the responsibilities of owning a house?
These are all questions that need to be answered before a comprehensive determination can be made. I would consult a real estate attorney to know exactly what his/your rights are.
Good luck, Jayjeemarie!!!