Valeria is one of the few people old Doom actually likes. He delivered her when Reed was captured by the Hidden Ones (an offshoot of the Inhumans) and no one else was around that knew what to do. Bven Reed couldn't stop Sue from miscarrying before (FF #267) and she lost the baby when Reed couldn't capture Doc Ock in time to bring him to the hospital. He wanted Otto there because he was/is a specialist in radiation. But with Valeria Doom was uniquely qualified since he is a master of science and and very adept at sorcercy, both of which was used to safely deliver Valeria.
Part of the reason why there is an affinity between the two is because of the tangled history of her conception and birth. When the FF were fighting Abraxas and the Ultimate Nullifier had to be used, along with Franklin using his reality altering powers, Sue became pregnant again. What we learn is that when Sue lost the baby in FF #267 during Byrne's run , Franklin intervened and with Roma's help and she was kept "In the Heart and Soul of of Eternity". She comes to the FF as the teen-aged Valeria von Doom, who comes from an alternate reality where Victor was Sue's second husband after Reed had died in some unnamed conflict. It's sort of assumed that Valeria von Doom/Valeria Richards are linked because of this. So it is very possible she has an affinity for Victor since part of her tangled history includes a period where there was a paternal relationship via Valeria Von Doom.