people's saying, "we stood and Allah stood with us", signifies that Allah (Exalted be He) helped them, gave them power and assisted them with His Guidance. This is, in fact, a valid meaning, but it is preferable to stop using this phrase to avoid confusion and misleading people. A Muslim may use a safer phrase such as, "we stood and Allah helped us in that."
people's saying: "O mother" when standing or sitting down is not permissible, because this involves calling out to an absent or dead person to help the caller achieve something and this is `Aqidah Shirkiyyah (creed that associates others with Allah in His Divinity or worship). Thus, a Muslim must avoid this phrase to protect his Tawhid (belief in the Oneness of Allah/ monotheism) and keep away from Shirk (associating others with Allah in His Divinity or worship) and its means.
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.