Hi thanks for your question.
is common complication of catheter insertion or removal.
You can apply hot sponging to the haematoma.
He may need prophylectic antbiotic to prevent haematoma from getting infected.Local application of heparin
ointment such as thromnphob or lioten gel will help in resolving the haematoma fast.
For pain he can use pain killer as prescribed by his/her Doctor.
Hope this answers your question.