You are right that your father’s transfer of the home to your siblings and you means that if your father applies for Medicaid within five years of the transfer, he will have a period of ineligibility. But the five years started on the date of the deed, not the date of the sale, so you have three years left.
The issue is now that you have divided up the proceeds of the sale, how do you make sure that everyone shares equally in paying for your father’s support, whether in your sister’s house or in a nursing home if your father has to move to one within the next three years. It’s just a fact of human nature that the longer each of you holds the funds in your own account, the more you will each feel that it’s your own money and be reluctant to share it. In addition, it’s at risk if any of you runs into financial difficulties, divorce, illness, or death.
We recommend that you agree together on how much to set aside for your father, erring on the side of too much rather than too little. Then put this money into a trust managed by two of you – four seems like a lot of people for coming to decisions. You would then use this money for your father’s benefit, distributing what’s left, if anything, to the four of you after he passes away.