Have you checked with your mother's lawyer.He should have the original copy,if she drew one.
How does the deed read? Does it say that your wife and your mother are " joint tenants" or
"tenants in common"?
If it states that they are joint tenants, then the property is likely your wife's.
If not, you will need legal advice. Have you filed her estate with probate yet?
Are there bank accounts, investmenrts, debts and other assets? You need a lawyer.
Don't do anything until you hire one. In the meantime, read the deed.