My son has Stage 4 tongue and lymph node cancer

So, in just 3 wks we went from thinking he had thrush, being treated to getting a biopsy and CT scan and finding out 2 days ago my son has stage 4 tongue and lymph node cancer.  Drs are talking abt removing his tongue and doing a free flap, a trach, feeding tube, neck dissection.  And worst case scenarios.  I'm a single mom, and this is my only child.  He was born with issues, and nearly died at 15 mos from meningitis, and developed autism after.  He is now 22.  Remarkable thing is, he doesn't look or act 'sick'.  He iss till going to work.  His surgery is dated Dec. 19.