Tawassul with deceased

Why did Umar RA asked Abbas to make dua during famine and not sought waseelah from the blessed Prophet sallallaahu alayhi wasallam?

Tawassul and Waseelah

Attributing rewards to others (Ithaalu Sawaab)

Food of Niyaaz / Fateha. Food in the name of other than Allah – haraam. But the transfer of reward to others is permissible.