Hi Alan,
I did not have radiation so will leave it to others to comment on your sisters issues with a swollen tongue.
I can however comment on your question regarding no one being able to give an estimate of how long this will last. This frustrated me also and I was often given the �how long is a piece of string� whenever I posed questions like yours.
Simple answer is everyone is different and I doubt if you will find anyone that can give you a timeline.
I also had a little swelling of the tongue/flap from surgery that did NOT prevent me from eating my pureed food earlier on. I did have a few de-bulking surgery�s for this mainly on the flap.
Is there someone on her team that you can talk to about her depression over this? She may need a little help with this.
Best wishes for her recovery and hope that it is a very short piece of string.
Gabriele