A mish mash of a problem

I don't really know where to start with this problem, all I know is i need some kind of advice .. My mum died 10 years ago and my dad fell to pieces, both myself and my sister have devoted the last 10 years to caring for my father, making sure he was never lonely, we have given up a lot of things and declined a lot of opportunities to do this... hence we both lived in the same house as my father... sharing all the bills etc... my father (who is 74) has had various mini relationships , since my mum died and 6 months ago met a woman ... since he met her he has become a different person (in a bad way) he has been moody, whenever he was away from her he always had the hump, sat there with a long face all the time, like he resented having to spend time with us, he kept saying things like he doesn't know what he'd do if she dumped him and that he'd be devastated and kept saying that he feels like shes going to dump him all the time (this was a bit heavy for me and my sister) then my dad won 77k on the lottery, and suddenly or rather inexplicably she wants my dad to move in with her... my dad didn't actually tell me and my sister this.. he spoke about it to his friends who all said we were old enough to look after ourselves (there's no dispute in that).. I think my dad even described us as baggage (conveniently forgetting we have given up 10 years of our lives!) we found out in a very round about sort of way that he was going to move in with this woman... this has left my sister in a very insecure housing situation as my dad is the tenant of the house and he thinks its ok for my sister to carry on living there and paying all the rent, bills etc... (my sister lives in London and would not be able to afford to rent privately as even renting a room in London can be £750+ a month) my sister ended up taking an overdose over all the stress, and has been very ill, she is only just getting better now and my dad is still moving in with this woman tomorrow.. im worried my sister is going to get ill again.. my dad has taken to telling bare faced lies and I just dont know what to do... any advice would be appreciated.

You all need a family meeting with full disclosure! If you sister cannot cope with that, you and your Dad do it alone. Remember, there is a reason for everything...Good luck on finding your blessings.

your dad will do what he wants to do,u cant stop just warn him that his choice may be wrong and that he is selfish,family meeting

Well just tell your dad with a smile if you can, if after you tell him with your sister ( if she can do it), that thank you so much for treating us your children like your maids this past ten years, because we can see that even through we took care of you. You obbessely think some random person ( insert person name) is loves you so much more, and we hope that you can be happy with knowning that you are putting your children out of a home and out of his life. Also that you there is no way that his girlfriend would ever not be interested in him even if he didn\'t have the money. Then for your sister and yourself find a cheaper place to stay, save up money. Remember that you are strong and that you can live on. Also that now you can move on in your life.