Heir blocking probate

We are trying to get probate court approval for administration of an estate
where the debts of the estate exceed the assets of the estate. The total
assets of the estate are about $10000, so the estate qualifies for small
estate administration in Texas. All of the debts are owed to us because we
paid for the funeral. The deceased has been ruled intestate because she
disposed of almost all of the assets controlled by the will while she was
still alive. The problem is that one of the heirs is refusing to approve
the assignment because she will not inherit anything from the estate after
the expenses are paid. The estate assets include a tax refund that we
cannot file for, some checks to the deceased and some money that we are
holding in a special account.
Our lawyer seems to be at a loss.
Any suggestions of questions we can ask to see how to get this kicked loose?
Can we file for the U.S. tax refund since the estate owes us money?