My sisters domestic partner of 30 years passed away approximatly 1
year ago. Although they were committed to each other, they were never
married. Her partner did have a living trust and named his sister as
trustee. The only real value left in the trust is a home free and
clear which my sister still resides. He noted in the trust she was to
be able to at this residence the rest of her life rent free. The trust
also states if she decided to move her and his sister would have to
agree on a sale price and the proceed to be divided as follows. 50% to
my sister, and the other 50% divided amongest his sister, son and
daughter. I recently agreed with his family members to purchase their
half for approximately $100,000. Can I do this by simply having his
sister (the trutee of the estate) sign a quick claim deed? or must I
do more? To complicate matters his sister has tranfered the title in
to her name and listed the house with a realtor. Would the realtor be
entitled any fees? the state and county this refers to Stanilaus
county, California.

You need an attorney, and possibly more than one.

The trustee probably should not have been able to transfer title to
her name if the trust held title. If this is a violation of the trust,
she could be removed as trustee for a breach of fiduciary duty.
Sometimes there are criminal charges, too.

Listing it with a real estate agent put her on the hook for commission, not you.

You seem to have a sensible idea, that of getting clean title out of
this potentially messy situation. Bravo. Life tenancies are squirrely
things when there isn't money in a trust for taxes, maintenance, etc.,
and should be avoided.

Thirty years and never married? Think of all the wasted income tax
deductions these two missed out on-- each paying single rates for
thirty years, not to mention the advantage of survivor benefits. The
tax savings would have put a nice amount of money in the pockets of
the heirs, if not your sis and her partner.