The text defines by deeds
The Qur'an defines people by what they do, not by what they declare they believe. When it names a category (the one who denies, the believer, the enemy), it at once describes it through deeds.
Sura 107 asks a question, then answers it with a deed: "Have you seen the one who denies the Retribution? He is the one who harshly repels the orphan, and does not urge the feeding of the destitute." (107:1-3). Denial is not an opinion: it shows in how the weak are treated.
Sura 90 does the same for the steep path: "It is freeing someone from a crushing debt, or feeding, on a day of hunger, an orphan near of kin, or a destitute person in privation." (90:13-16). And those of the Fire say of themselves: "We were not of those who made contact, nor did we use to feed the destitute" (74:43-44).
Kinship or marriage does not replace the deed. The wife of Nuh and the wife of Lut are given as an example to those who disowned (66:10); the wife of Fir'awn, to those who believe (66:11). Each is judged on what she did, not on the man she married.
Even the enemy is defined by deeds: "those who fought you concerning the Law, expelled you from your homes, and supported your expulsion" (60:9), and not by what they believe.
In the text
فَذَٰلِكَ ٱلَّذِى يَدُعُّ ٱلْيَتِيمَفَكُّ رَقَبَةٍإِنَّمَا يَنْهَىٰكُمُ ٱللَّهُ عَنِ ٱلَّذِينَ قَٰتَلُوكُمْ