I say, and with God's guidance: It is considered a permissible act due to the need and necessity for such service to the elderly. If the person performing the work takes good care of them and has a sincere intention, he will be rewarded by God Almighty for his work, provided that a male does not see the private parts of a female among the elderly, and a female does not see the private parts of a male among the elderly. And God knows best.