My mom had her thyroid removed (completely) and she was just fine. It means that she has to take medication for the rest of her life, but people with thyroid problems have to do that anyway (myself included). From what I understand, the only time they choose to remove it is if it cannot be controlled with medication (for example, the levels fluctuate too much) or if it is so enlarged that it becomes a problem for the person. There may be more, but that is what my doctor explained to me.

I had never looked at a thyroid as two parts of one gland, and never heard it referred to in pieces like that. However, it is a buttlerfly shaped thing at the front, lower part of your throat, and if you look at it you could kind of see that the two "wings" of the butterfly could equal two parts. Perhaps he was only have issues with one half and they were hoping that he could retain some of the function in the other half?

Either way, he'll be perfectly fine, with a normal active life, as long as he takes the medication and gets checked as per his doctor's orders so that they can adjust it if they need to. It is easy to get used to and very simple.

I'm really surprised that your doctor didn't fully explain all of this to you guys. I'd suggest you sit down with him and have a log conversation so you both are completely comfortable, or get a second opinion from another endocrinologist.