There's no way this will succeed.
I believe you are absolutely right. One is a sans-serif typeface. Further, they are used in different products and markets, so no brand confusion can result. A drawing of the mark and/or a description needs to be submitted with the Registration Application.
For example "W" is also a trademark of:
AND:
Word Mark W Goods and Services IC 036. US 100 101 102. G & S: Investment advice; investment management; financial portfolio management; financial research, analysis and consultation; investment research and analysis; investment consultation; investment trust management; financial forecasting; investment of funds for others
They need to get slapped for abuse of process and vexatious litigation.