He is a mahram for her and they can stay alone together, travel together, and uncover her hair infront of him. Unless you are accusing your father to
be a filthy pervert, there are no grounds for such worries.

I know in islam like my father wud be a mahram to my wife but like is it like a real mahram or not really, like how i am to my mum because i have a young father 45 years old and now he is not married and despite that i would not like them to mix or be near each other even though i am present what is your opinion? And vice verca with my wifes mother?