I think your answer is right in front of you -- just do for your son what your mother did for you. I was raised as you were, and I had a brother who could not eat many foods as a child. He grew out of that with time and was eventually able to eat anything. My mom never made a fuss about it. I didn't either with my children, in spite of serious in-law criticism. I tried to have choices by serving leftovers. So my non-pasta child ate yesterday's chicken when we had pasta, and my non-meat eater had pasta when we had chicken. We also went through a phase of plain pasta only -- very boring, so I just set up a series of bowls with things to add -- veggies, cheese, sauce, etc. -- another way to have a "different" dish each day without having to cook it. My children are adults now and eat all sorts of things. We laugh about the things they would never eat at home but tried when out with friends or at a boyfriend or girlfriends home as a guest. The key is not making the food a big deal -- the important part is being together for a meal and sharing time together that is fun. As long as pasta is the only thing that he doesn't want to eat, it's not a behavioral problem. And, from what you said, he is willing to try a few mouthfuls.
You might ask him -- not at dinner time -- why he doesn't like it. Is it the taste, the texture, the smell. Does it make his stomach queasy. Gather some info and talk to your pediatrician. His dislike might have a physical reason, such as gluten intolerance. He might prefer white pasta, or perhaps a multigrain that has a lighter taste.
I am sorry for the loss of your mother. My father passed away this spring in the early stages of Alzheimer's. My mother misses him terribly, but she has a wonderful group of friends who make sure she gets out to lunch, the senior center, and her exercise classes. They also invite her to their children and grandchildren's sporting events and concerts. I hope your father lives nearby you and can spend time with his grandchildren.
Good luck. Your husband needs to support you on this. Divided parenting leads to an issue becoming larger than it is because your children will quickly see when you disagree. Get him to focus on making dinner a good time with dad; talk about what he did today, about sports, etc. Even though they are little, they will pick up some of it, and most importantly, they will know that dad wants to spend time with them. That's more important than pasta.