Based on the document that tagteam referenced (which is not authoritative CT DRS guidance), it appears that the number of days spent in Connecticut is not going to matter in your client's case. The significant issues are going to be whether the assisted living facility constitutes a "permanent place of abode," and whether the client Y's domicile has changed. That could depend on whether Y intends or expects to return to Florida.
I suggest that you tell the client to consult a Connecticut tax attorney to determine whether he or she is a Connecticut resident for income tax purposes. You should not make that determination yourself because (a) it's a legal question, and you (apparently) are not a lawyer, and (b) you don't want to be the responsible party if the CT DRS disagrees or the client later questions the residency status. To protect yourself, get the determination of residency in writing from the client or the client's lawyer. You might want to consult your E&O insurer about how to handle it.
