Just a few comments.
Shin...perhaps not the commonest place for a BCC.
Did he have a skin graft to the resected area on his shin following the excision?
Is the resected area painful and inflamed?
The "regrowth of flesh" is good news.
"Huge amount of clear fluid", does seem odd but may depend, as mamya states that it may be a part of the healing process.
Is the opposite ankle swollen?
All in all, depending upon the answers to my question, this is no big deal, just monitor the situation over the next 7-10 days.