my fiance and I owned a home together deeded as : JTROS. His mother is handling the estate so we are using the same lawyer who is helping the family.

Although you did not say, can I assume that your fiance died?  If tat is the case, this is occurring because you were not married.  therefore, you were not related to him at the time of death and will owe inheritance tax on the portion of the house that you inherit from him.  Inheritance tax is based on the relationship of the decedent and the beneficiary and it will be about 15-16% depending on the amount of tax due.  If you can prove your contribution, then that may reduce the amount of the inheritance and therefore reduce the amount of the tax.