Dictionary of Spoken Russian/Russian-English/Section 18
§18. ОН
The pronoun он has this stem in the nominative forms only. All the other forms have a stem [y-]. The Pn form has the ending [-ji]. The Fg and a has the ending [-оуo]. The F endings have [e] instead of [o]. All the accusative forms, regardless of gender or animation, are the same as the genitives.
| Mn | он |
| g | его |
| d | ему |
| i | им |
| l | (нём) |
| Nn | оно |
| Fg | её |
| d, l | ей |
| i | ей, ею |
| Pn | они |
| g, l | их |
| d | им |
| t | ими |
After prepositions the stem [у-] is replaced by [nj-]: от него "from him," с ним "with him," в нём "in it," and so on; excepted are the g forms as possessors of a noun: от его брата "from his brother," у её брата "at her brother's, in her brother's possession," в их стране "in their country."