Thank you for your question
My name is Clare
I shall do my best to help you but I need some further information first
How much is the property worth and how much do you wish to pay?
How old is your father and what other assets does he have?
Is there currently a mortgage on the property that you wish to purchase?
i am afraid that that is not possible.
If you are going to have a mortgage then the property will have to be transferred into your name and the existing mortgage will have to be paid off before the new mortgage is issued.
In essence it is indeed possible for your father to sell you a share of the property - and you could either get a new mortgage jointly with him - or the property can be transferred into your name and there would be a Trust Deed confirming that your father retained a financial interest in the property.
Please ask if you need further details
If you get a joint mortgage you will not need a separate Deed - and yes you will be able to specify unequal shares
You are most welcome