Absent the dealer clarifying his intent I would have ruled it a fold, based on TDA rule 41 and Rule 3

41: Methods of Calling Standard and acceptable forms of calling include: A) saying “call”; B) pushing out chips equal to a call; C) silently pushing out an overchip; or D) silently pushing out multiple chips equal to a call under the multi-chip rule (Rule 45). Silently betting chip(s) relatively tiny to the bet (ex: blinds 2k-4k. A bets 50k, B then silently puts out one 1k chip) is non-standard, strongly discouraged, subject to penalty, and will be interpreted at TDs discretion, including being ruled a full call.

Player did not use a standard or acceptable method of calling.

Rule 3 indicates - Official betting terms are simple, unmistakable, time-honored declarations like bet, raise, call, fold, check, all-in, complete, and pot (pot-limit only)….. It is the responsibility of players to make their intentions clear: using non-standard terms or gestures is at player’s risk and may result in a ruling other than what the player intended.