1,264. Losing a Relative on Shabbos
196:8 If a person lost a relative and became an onen after the time for morning prayers arrived, if he didn't yet daven and he will be an onen until after the time to pray has passed, he does not need to offer a compensatory prayer by davening the next Shemoneh Esrei twice. The same is true for mincha and maariv.
196:9 If a person lost a relative on Shabbos, since the deceased may not be buried that day, he doesn't become an onen, so he may eat meat and drink wine. He is obligated in all mitzvos other than marital relations, which are forbidden to him. He is also not allowed to study Torah. These things are prohibited because they are private. (Editor's note: public forms of mourning are forbidden on Shabbos.) If he is a chazan, he does not lead the service if someone else is able to do so; if there's no one else able, he may. If the deceased is one of his parents, he may say Kaddish in a place where there are no other mourners; if there are other mourners, he may not say Kaddish before the burial. If the onen is already a mourner for his father or mother, or if he has Yahrzeit that Shabbos, then he says Kaddish like anyone else would do in that situation.