Hello.
I am so sorry for your loss. I can imagine how difficult it must be for you now, losing somebody we love is not easy, especially as you said he was your best friend as well. I understand that you wanted to be with him and spend more time with him as well. However due to the current situation you were not able to, I understand that is hard for you to accept.
Allow yourself to go through what you are feeling right now, grief is not an easy process. However all your feelings and emotions are valid at this point, do not deny them, allow them to flow.
Next Steps
It is important that you do not suppress what you are feeling right now nor you keep them to yourself. Talk to someone you feel comfortable with and trust. Do talk about your father to them, all the memories that you want to. It can be difficult to do so, however allow them to be heard. This will help you to deal with what you are going through better.
Health Tips
There is no right way to deal with grief. All your emotions and feelings are valid. Do try writing your feelings and memories in a journal if you can, the idea is never to suppress your emotions but to let them flow. Please do reach out if you would like to talk. Take care.