How should a woman wash her hair when doing ghusl from janaabah?

Her hair is falling out and washing her head harms her; how should she do ghusl following menses and in the case of janaabah?

How to do ghusl from janaabah

Is it necessary to do ghusl after having an ultrasound tube inserted into the vagina?

He did ghusl just to be clean, and he did not realize that he was junub. Should he repeat his ghusl?

He suffers from too many wet dreams; he wakes up and finds wetness but he does not remember having a dream