Hi Jemi,, your Dad is so lucky to have you. This operation is so huge and life changing. My Kris had this surgery in March '12 and it certainly is life changing. Your Dad has so much to deal with . Kris still has swelling around his throat / neck area. Somedays are worse than others. We were told that it would take at least 9 months for this to subside. At 2 months post surgery he was still hugely swollen. I wouldn't worry too much about this.
As for the alcohol. I guess all you can do is reiterate for love for your Dad and let him know that his drinking upsets you and is probably not good for him in excess. Really, if its going down the PEG it won't be detrimental to the surgical area and won't have an affect on those tissues. Your Dad Has to want this for himself. Do what you can to help yourself deal with this and it sounds like you are.
Honestly I can understand why your Dad is drinking, he is comforting himself the only way he knows how. Until he is ready to get help for his alcoholism there is nothing you can do. Just let him know that you are there for him.
This beer dumping won't be affecting the lymphoedema.
Take care and keep in touch.
Tammy

Caregiver/advocate to Husband Kris age 59@ diagnosis
DX Dec '10 SCC BOT T4aN2bM0 HPV+ve.Cisplatin x3 35 IMRT.
PET 6/11 clear.
R) level 2-4 neck dissection 8/1/11 to remove residual node - necrotic with NED
Feb '12 Ca back.. 3/8/12 total glossectomy/laryngectomy/bilat neck dissection/partial pharyngectomy etc. clear margins. All nodes negative for disease. PEG in.
March 2017 - 5 years disease free. Woohoo!