All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
In principle, it is impermissible to eat from the wealth of the orphan, but an exception is made by Sharee‘ah to the guardian of an orphan's property, who is allowed to eat from it according to what is acceptable if he is in need; Allaah The Almighty Said (what means): {And test the orphans [in their abilities] until they reach marriageable age. Then if you perceive in them sound judgment, release their property to them. And do not consume it excessively and quickly, [anticipating] that they will grow up. And whoever, [when acting as guardian], is self-sufficient should refrain [from taking a fee]; and whoever is poor - let him take according to what is acceptable.}[Quran 4:6] Hence, in principle, the non-guardian of an orphan's property is not permitted to eat of his property. That the orphans are not pleased with others' abstention from eating of their property does not count, for none of them has the right to give permission concerning his property before he becomes of age.
But the advice we give here is that whoever visits the orphans may bring to them something of food or other valuable gifts of money or clothes, which allows for him to mix his affairs with theirs, so that what he eats would not be more than what he gives. Thus, he combines both things. Allaah The Almighty Said (what means): {And they ask you about orphans. Say, "Improvement for them is best. And if you mix your affairs with theirs - they are your brothers.}[Quran 2:220]
Allaah Knows best.