Unassisted is definitely the only one that counts. Your surgeon already proved what your knee is capable of doing. What you can do (not what the therapist can do) is what matters now. After all, you won’t have anyone at hand to bend your knee that extra few degrees when you are up and about, using your knee.
There won’t be many times like this in your life. Your time of need will pass. Rather than think of yourself as a burden, why not think of your loved ones as blessings? You have an amazing family! I smiled just reading about them, and especially your grandmother. How wonderful that she can help! Your son is learning some priceless lessons, too, about family and doing for others.
As for your sense of humor... that’s the most powerful weapon in your arsenal! If you can find the humor in the day to day (... to day... to day) of recovery, you are mighty indeed.