Two friends gone, one through oddness, and the other by passing.

[No Vested Interest]

1. So very sorry you have had this loss and hurt of losing your friends.

Do not blame yourself for the death of your friend.
He obviously had physical problems for which you are not responsible, and for which your intervention likely would not have solved his problems.
You are wise to keep the door open.
Sometimes we don't know and may never know what caused the perceived (by her) problem between you and her. It likely is/was a misunderstanding of a word or a gesture or look or some thought put into her mind by another.
We sometimes just have to accept that misunderstandings are part of our human condition and sometimes things may go wrong that may never be completely set right. - Hard to accept.
(I have had a friendship abruptly ended as well, over the telephone, with no reason given. And though I miss the friendship, for we did certain activities together that my other friends have little interest in, I recognize that she was particularly sensitive and may have interpreted something I did or said (or didn't do or say) in a negative manner. It happens, and it's too bad.

Mourn for the friends you have lost. Then find peace in those who know and love and have concern for you. There is still much to celebrate in our big, beautiful world.