I care give for a friend with Alz. I need help. Should I ask or tell her I’m going to hire a caregiver to help part time?

I think her stage of cognitive decline and your status as POA drives the type of conversation your have. I hope you already have her POA in hand. Assuming you do and her cognitive decline is such your friend can no longer make decisions in her own best interest, I would have a conversation where you discuss the care giver that will be coming. If she still has some good cognitive function, then maybe you open the conversation with the need for a care giver and seek her agreement/approval.

Your friend should be paying for the help any in home care giver you hire provides, one of the reasons I hope you already have a POA in hand if your friend is no longer managing her financial matters.

Is she paying for the caregiver?