can we get a care giver a day or two per week

my sister-in-law is taking care of her mother and father (mom has dementia and incontinence and dad is a diabetic with vascular disease, almost blind with Macular Degeneration, hearing loss and heart issues) and she takes care of her aunt and uncle who live in another town ( she also suffers with sever dementia and he has one lung,on oxygen and requires a wheel chair) to make matters worse she suffers from Lyme disease her self. she is at her whits end and it totally burnt out. Will medicare benefits cover someone to come in a day or two a week to give her a break?