PROS/CONS of using standard forms for Trusts, etc.

PROS/CONS of using standard forms for Trusts, etc…
We have a friend who is an attorney who says he will prepare our Inter Vivos Trusts, advanced medical directives (living wills) and powers of attorney for each other for me and my husband, for $1,600.00. My husband thinks we can just buy the forms at an office supply store and do them ourselves and save a lot of $. What would be the pros and cons of this and is $1,600.00 a reasonable cost?

will my mother has alzheimers real bad and a will and living will were written…

will
my mother has alzheimers real bad and a will and living will were written with dad sane and mom. Dad died 06/01/07 my one sister is executor and I’m second . Today I found out she went to the bank to get a new will notarized taking me out and putting in another sister with out my consent . As executor can she sign under my mothers name (because of the alzheimers she signs for mom. ) can she take me off my mothers will and living will ?

All estate papers done by attorney and were properly executed some years ago–…

All estate papers done by attorney and were properly executed some years ago– Last Will and Test, Living Will, Durable POA and Desig of Health Care Surr. As currently reads, all duties and respon, accross the board, on all docs to be shared and/or decided by son and daughter. I wish to replace son with sister on all docs. Can I do so with a codicil to cover all four docs or do I need to redraft?