You have my heartfelt condolences. I lost my mother about 9 months ago. People act very strangely when faced with this situation. Glad to hear that you came to the understanding of his motives, and they were not negative.
I hope you continue a good relationship with your stepfather.
My father and father-in-law both passed first. After my mil passed it certainly stressed the relationship with my wife's siblings. I had to keep reminding myself that my sil was having a hard time dealing with everything and cut her some major slack from time to time. I'm sure she thought I was as dumb as a box of rocks too!
Hold on to your faith, remember the good times.