Help for carer

My dad is 83 and has cancer which has mastetised to his spine.  He was diagnosed four years ago. He is in pain but in the past two weeks he seems to be taking a downturn.  He is too weak to walk far, falls with weakness, wont really eat or drink much and has all the last signs of late stage.  He sleeps most of the time and is beginnning to get confused. He also coughs up large amounts of dark phlem which may indicate its in his lungs.  He is being cared for at home by our mum and is expecting a visit from Loros soon to assess him.  My brother visits often as lives near, but I am four hours away.  We are wondering if anyone has information as to how long he may be with us and whether I should now be thinking of being with them full time.  Its so hard to know what to do.  Has he got weeks or months left and is this a sign he is on his way out?  Sad to post this but just after any experiences poeple may have to give advice.  Many thanks and love to you all.  Emma