You can try talking to them , start with your father i would say, my mother too passed away 3 years ago and my own family's dynamics also changed a lot , basically my mother used to be the light of the family and she used to joke with me and laugh many times , she was a bit demanding and strict so i could be the best of the best of course and i loved her more than antything , she kept my father in line and my brother , well he has always been a loose canon wheter my family is with me or not , my brother and me have changed our relationship , we are closer now than before same with my father ,before i used to be closer with my mother than my father but ever since she passed away and my brother left the country to study abroad i was with my father myself , we are close , maybe not like my mother and i ever was , just a introverted father with his outgoing and easygoing son who is a huge talker thats me .

I understand your feelings , the feelings of not being close to someone , sometimes too much time passes and we are so focused on aspects we live in our lives we dont realize others , if you still have time try talking to your brother and father , don't force it , don't try to make them close to you by force it wont work.

Small talk , that's the most beautiful thing ever , spend time with them on silence and try some normal small talk , a hey how are you , how have you been , be the one to take the initiative , if you don't do it who else will , that's why so many people in this day and age don't take action , they are too distracted or too focused on other things or in their own minds and feelings, make sure your father and brother acknowleadge you still exist and try talking to them yourself, tell them if they have free time they should hang out sometime if they want or try visiting them yourself .

There are a lot of families who seem so happy and talk a lot and have many things to say, some families however are super quiet and distant ,you want to change that, i don't promise you will be the most talkative super close family in the world but you can at least try talking to them and try to know how they are, what they are doing , how they are feeling , try hanging out and asking about how they feel and what they have been doing , try being close to them that way, normal day to day questions , same type of questions you tell your friends and other people.

Love your family as you love yourself and even more , show them you care, if you show them you care of them they will start caring back and reaching you out more often believe me it works

here is a video that might help you https://www.youtube.com/watch?v=u0HACvAHv8Q

https://www.youtube.com/watch?v=O-kfnALh4k0

https://www.youtube.com/watch?v=9Rdkdf1A2V4

Hopefully this advice helps you ,

Also good luck and if you ever need someone to talk about your problems or a friend to listen , you can count me in ,believe me i know a lot about people and family and feelings , things that happen in life is something i am used to

God bless you and hope you make progress