My wife's brothers built a house in Texas in 1975 for their widowed mother. Title was placed in the name of all 7 brothers and sisters, including my wife. My wife's mother lived in the house for 20 years until she could no longer live by herself and came to live with us in 1996. Title was transferred to my wife and me. Mother died in 2007. We kept the house for a while as a vacation retreat but sold it last year for $144.000. Now need to pay capital gains taxes but no idea of original cost basis. Would it be acceptable to estimate the original cost based on 2022 property tax assessment ($99,000) and using construction cost indices for 2022 and 1975 - this would result in an estimated cost of $12,000?
