We love each other but his dad won't agree

I have fallen in love with a boy and he has fallen in love with me. We have been in contact since the last 15 months, basically a relationship. Our families are not only related (fathers are cousins) but both fathers are best friends too. My dad is from Pakistan and the boy is in Pakistan too. I first met their whole family when I was 18. He is a single son and 6 sisters (3 married and living in UK now). We started talking during a trip I took to Pakistan (I go often with my dad as I really like it). When I am with his family it is like I am already apart of their family. we are really really close, I am close with all his 6 sisters. I take pictures with his family, his parents, grandma (My paternal grandads sister). As the months went by, I told his sisters about us as didn't want to keep us a secret completely and he directly contacted my mum to say he loves me and wants to ask for my hand. (My mum knows nothing of us talking). My mum is more than happy with him, as he is mature and his family is already close to me and their personalities match ours. Basically, Match made in heaven. He told his mum first that I am the girl he likes and wants to marry, his mother disregarded it as because she already knew his dads opinion. He went ahead and told his dad too, and he was shocked. Because he is the single son, the plan was to Never 'send him' to the UK after marriage. They are wealthy back home and he will get everything. At first his dad said his age is young, he is 19 and I am 21.. he then asked again in some weeks and his dad replied with he has everything in Pak and doesn't need to marry from the UK. I understand the inheritance thing, but now our feelings are uncontrollable. He has asked once again and his dad said I am a nice good girl but no need for UK and has gotten upset about it and still being stubborn and not agree to it. We are both heartbroken, as I took the choice to cut us both off from each other, as we can easily stay happy in love for the next 5 years while I deny all other marriage offers, but the risk is too high and his dad could still say no in 5 years. I admit I pressured him to talk to his dad, as I was getting offers for marriage. He says I am pretty and I can see he is a bit insecure with the guys who ask for me (anyone would be!). His dad, I respect and love him a lot too as my uncle, but he will not change his mind. I just don't know what to do. I really don't want to lose him. The only person who does not know that he likes me, in both of our families is my Dad, as he is protective and he will only be interested in these things if they proposed otherwise no need to tell him.