Theo wasn't usually seen at the Ministry on Sundays, not unless there was some project he was interested in going on that couldn't be haltered for the weekend. No Sundays were for spending time with his family, for socialising, for working on everything that wasn't Ministry related, like the businesses and estate.
When reading that Potter was dead, however, he decided today might be one of those Sundays when he visited the Ministry. He saw the body, went to work in his office for a while, talked to people in the building, in his Department, found out as much as he could without seeming more curious than anyone else. Being a member of the Wizengamot helped when finding out information.
When returning home an hour later, he went into his office, shut the door firmly behind him before sending a Patronus to Severus.
"I'm sure you've seen the papers by now, and I can confirm that the news about Potter's death are correct. I witnessed his body myself today.
More so, I found out that they're keeping one of yours in the cells of the Ministry, Emmeline Vance. She was still alive last I heard an hour ago, provided that my information is correct.