I believe that surgery should always be a last option even if that suggestion comes from a doctor. If i were you, i would covered all other options as you mentioned...
-You should find a massage therapist who works with kids, have one session with them and ask them to teach you how to do Transverse Friction Massage – that should be performed across the nodule/adhesion on the affected finger to help break it down, reducing its size.
-You should learn the appropriate Stretches – Immediately follow Transverse Friction Massage with passive and active stretches to the affected finger to help thin the tendon.
-You should learn the appropriate Exercises – Immediately follow the stretches with active strengthening exercises for the OPPOSING MUSCLE GROUP, in this case the extensor muscles that extend the fingers and wrist, in order to hold and maintain the length to the tendon that you just stretched
-Hydrotherapy – Ice the affected tendon in a stretched position to maintain the length of the tendon that was just created through the stretches and exercises. Icing the tendon also removes swelling and toxins created through the use of massage, stretches and exercises. Ice the tendon no longer than 1-2 minutes. Take a break for 3-minutes and repeat the ice cycle two more times.
I think you should get a second opinion as well before you get your baby in a surgery and to make sure the diagnosis was correct (yes, doctors make mistakes too).
All the best and good luck!!
L.