I have to say that your story reminds me of my experience when we got Ella about a year and a half ago. The biggest difference is that Ella was only 6 months old and your Sid is 7 years old. If you click on my past posts you will see one called "gender preferences" where I described a lot of the same problems. I did the majority of the feeding and walking, but Ella treated me completely different than my wife. Ella was definitely fearful of me for several months and it really can tear you apart.
All I can say is that it took about 6 months but Ella eventually began to slowly become more comfortable with me and I am now her second favorite person in the world (behind my wife, of course). She definitely used to cower away from me anytime I approached. And this went on for months.
Here are a few random suggestions that I think helped us. Hand feeding meals. I spent about a month or so feeding Ella most of her meals from my hands. She had to trust me enough to come up to my hands to get her food and eventually associated it with good things. If Sid has any REALLY favorite treats they should be reserved just for you to give him and nobody else. Obedience commands. I think this is the thing that really gave me a connection to Ella. If Sid knows any commands work with him a few times day with treats to run him through his tricks. If not, work on teaching him a few basics–it is a great way to bond. One of the first things I would try to teach is the command "look" to get him to give you his attention. You can't do anything with a dog without his attention. Ella used to look anywhere but at me. "Look" taught her that giving me her attention was a good thing.
At the time I was going through this I would say that I could deal with it as long as I knew that eventually everything would work out OK. It was the uncertainly that was killing me. They say it takes a lot to earn a Basenji's trust but that once you do earn it you have it for life. Basenji's are smart. Eventually, Sid is going to learn it is best for him to trust you. Good Luck.