My father owns a small home and has a bit of cash assets. He has a will leaving 2/3 to me, his daughter and 1/3 to my brother. His theory in leaving me more is that I care for him so he is able to stay at home rather than enter a nursing home. I am his power of attorney and executress.
His care is getting more demanding and he would now like to give me his house now in appreciation for all I do as my brother rarely visits or calls but is insistant on knowing if his will is "50/50." My father is of very sound mind and I remain neutral and do not comment on his ideas.
What is the best way to sign over the deed to me to prevent my already digruntled brother, who I assume would pursue legal action when after my father passes and he is informed his share is 1/3 and not 1/2, and should my father keep the will in place and would it divide any assets other than the property at 2/3 and 1/3?

I would consult a real estate attorney on this. I think the best choice is to establish a trust in your name and put the house in it. This would take the house out of the estate but offer the best tax consequences. If he gives you the house now, there may be adverse tax consequences. He will then need to rewrite his will to exclude the home.

He can't just sign over the house while he's alive without paying dearly in gift taxes.
A trust is certainly an option, and has it's own limitations and will incur fees from the bank.
I agree that you should talk to a lawyer, probably the one who wrote your father's will.
Your brother can contest the will, dragging it out, even if he loses.
Your dad can give you 13K a year tax free, so he could do 1 in the next 2 days and the 2nd on Jan 1.
Another idea: he can sell you the house and write you a mortgage using rates set by the IRS for an intra-family loan. The rates are low and vary monthly and by term (I think < 9 years and 9+ years). You could have any term regardless of how long he lives. That way the house is in your name now. You need a formal appraisal for a sound legal basis for the price. When he dies, the mortgage is on the list of assets, so you will have another appraisal and (possibly) owe whatever fraction the will states. If there are enough other assets, then you get your own debt back as your share.
I'm not sure if any of this really matters when it comes to contesting wills, or if it's worth it.
One thing I might consider is a videotaped conference of your dad and his lawyer attesting to his mental state. Doctors, anyone.

I forgot - a key question is whether you want the house specifically, apart from cash assets.
If so, especially if you are living there and want to stay, then it might be worth it to do a trust or buy it from him now.
If he leaves it to you in it's entirety in the will and your brother contests, what will happen will depend on many factors. But you being there to care for him, with testimony from others, will stand a good chance, I think. And he can't force a sale or do anything meanwhile.