Definetly good advice given about getting a lawyer. As stated get an estate planning lawyer. Also, have everything put in a trust.. If not , everything has to go through probate. A lot is involved when going through probate.
Some lawyers shy away from trusts because they make more money doing probates. Also, check and see if your state requires you to pay inheritance and estate taxes. Some states don't take in these taxes. Florida is one of them.
Make sure your father has a will and power of attorney drawn. If he is of sound and mind, have him do it. Make a couple copies of originals with signatures. You want to keep originals. Depending on your state , some won't accept a copy of the will
, so everything might have to go through probate. Have someone in the family be executor and someone be power of attorney.
In reference to investments; call up every investment company your father has and update all beneficiary forms. Also, request power of attorney paper work. Fill those out and send to each investment company along with a copy of the
power of attorney forms.