As we know, according to the law only an advocate shall exercise court representation or its organization as a regularly provided and paid service.

But this rule has its exceptions, in particular,

1) representation of close relatives, including parent, child, adopted, adopter, brother or sister, grandfather, grandmother, grandchild, spouse or parent of spouse, as well as husband, daughter in law or son in law, without compensation.

2) Representation in court the legal entities predominantly owned by close relatives.

Persons other than advocates are prohibited from representing clients in criminal cases.

Source: iravaban.net