I've had the NG tube many a time. It's a very easy way to take in nutrition. Not nice going in but skilled nurses can insert it almost without you noticing. It's not uncomfortable once it's inserted. Your husband will feel a sense of relief once it is in and he is getting the nutrition he needs. He will still be able to sip water and so on.

Best wishes.

1996, ovarian cancer surgery + cisplatin and taxol.
September, 2007, SCC of left lateral tongue. Excision.
October, 2009 recurrence in scar tissue, T1NOMO. Free flap surgery from left wrist - neck dissection. 63 year old New Zealander. No chemo, no RT.
February, 2014. New primary in left buccal mucosa. Marginal mandibulectomy, neck dissection, right arm free forearm flap. T1N0M0 but third occurrence and some areas of concern: RT started 8 April and finished 19 May.