There is no way for anyone to tell whether this was done correctly. Take the deed from your father's estate and the quit claim deeds to an attorney and let him review them.
Life estates are full of potential problems. If you mother goes into a nursing home or is incompetent you and your sister may not be able to sell the house. There are also issues of insurance, maintenance taxes etc. If she goes on Medicaid, even a life estate can be attached and a lein placed on the house.
This is a good time to have an attorney review all of her paperwork. It will make it a lot easier on you and your sister.

