My son

If this was me, I'd find a way for your Son to receive a covid vax ASAP before trtmnt. (consult/confirm w/Oncologist but from reliable sources, a good idea)

Re: Hair UPDATE: My orig comment "don't fret-it; it grows back" was directed twds your son's possible hair loss.
[My Opinion] Hold-off on YOUR buzz cut.  You have enough to deal with as a stresed Mom who cannot be there PHYSICALLY for him. If Dad wants to go dome-head, let him but don't feel obligated. (regardless of age, I would feel even worse after such a diagnosis if my mother shaved her head to "support" me.)

Suggestion: Spend some time on this forum. Read up on the trtmnts specific to his diagnosis.
Don't be afraid to inquire to the ONC or Hospital requesting the specific pathology that led to the diagnosis and his specfic trtmnt plan. (then it will be easier for forum members to accurately share their experiences)
EG: (me)  NSHL Stg 4 Nodular Sclerosis Hodgkins Lymphoma  (Quick google states there are 4-5 types of HL in addition to non-Hodgkins Lymphomas)

Some patients like myself - (disclosure - was already balding) retain most of their hair thru trtmnt.
At 9th trtmt of 12 (stage IV), stopped shaving at the suggestion of a nurse and by end of my trtmnts, really proud of my patchy pseudo-beard. I continued growing it for a year and eventually resembled one of the Smith Brothers (cough drops) before shaving again.

As mentioned above in my update, I imagine the diagnosis is harder on you, than your Son.
Assuming he's receiving ABVD, it's a well-tested (efficacious) trtmnt and reliable.
Clarity: Stage II is typically 4 cycles (8trmnts spaced 2wks apart) and if there are no delays, completed in <4mths (16wks)

All the best

Ps: Find out if he will be receiving Neupogen or Neulasta.  (post answer in this thread)
Also inquire if a mid-trtmnt Pet Scan is or will be scheduled. In some cases, the "B" (one of the 4 chemos) in ABVD regimen can be removed for the final Two cycles (4 trtmnts).

Pps: Some of this may sound like gibberish. After that first trmnt, the schedule terminology as well as the chemo recipes will make more sense.
Ppps: That vax suggestion goes for yourself and his father, too.

My advice is not to.My husband shaved his head after he shaved the rest of my hair off.For most guys it's really not a big deal. he did continue to buzz it a few times.At the current time he has a full head of hair and mine is 1 1/2 inches.It will be a long time for me to grow it back.It's not my identity but I really miss my hair!

karenross said:

I would not shave your head. 

I would not shave your head.  In 1989 I was diagnosed with Hodgkins Lymphoma stage 2b and underwent chemo.  The Dr said I would lose my hair so I decided to get is cut super short so I wouldn't be clogging up drains with all the shedding of the hair.  Guess what, my hair got thin but I never lost it, still regret shaving it.  Now, 32 yrs later I am dealing with a brain tumor unrelated to the Hodgkins and I just completed radiation.  I learned my lesson and did not cut my hair.  While I have lost some it's covered up by the rest of my hair.  

I've always regarded the somewhat popular practice of 'sympathy baldness' as gimmicky, and of no supportive value.  I understand the motivation, which is laudable.  It is usually done when the patient is a youngster or young adult.  I think if the people around me went bald, it would make me think MORE of baldness and its significance, not less.