If your father's estate is only $1M there will be no federal estate tax. The exemption in 2013 is $5.25M. CA has no inheritance tax.
However, probate of his estate will be expensive and cause delay in distribution. It would be much better for your father to transfer the house, and his other property, into a trust so that probate can be avoided.
I do not suggest transfer in any other fashion as it cannot guarantee the results your father seeks and could have adverse consequences regarding your father’s eligibility for government benefits, should he need them, and expose the property to creditors of the intended beneficiaries. There is also the issue of favorable property tax treatment and capital gains tax treatment that needs to be considered and maintained.
IMO, your father should consult an elder law attorney to prepare the necessary estate planning documents to accomplish all the beneficial purposes that are available. Making a misstep in the process can be extremely expensive.
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If your father does not have a living trust and no other names are on title then it will have to go through Probate. I agree, that there doesn't appear to be any estate tax implications. If the house is transferred prior to death there may be Capital Gains tax implications. A Living Trust is normally a good vehicle to use for transferring assets. Your father needs to see an experienced estate planning attorney.
No legal representation exists by virtue of this answer. It is recommended that you contact an attorney directly for a more complete response.
Your father definitely wants to set up a trust. I assume that this is not his primary residence since one option is to sell and distribute prior to his death. That being the case the last thing he should do is that option. It will likely result in adverse income and property tax effects. See a good attorney, it will be well worth the money.