Is it permissible to combine the salary of my deceased paternal uncle's daughter, which is 120 Jordanian dinars, with my salary, given that she and her mother live, eat, and drink with me?

You should give the money to your female cousins if they are adults and of sound judgment, as Allah, the Almighty, says: (And test the orphans until they reach the age of marriage; then if you perceive in them sound judgment, release to them their property). It is not permissible to dispose of their money except with their permission. If they are not adults, then beware of consuming the orphan's money unjustly, as Allah, the Almighty, says: (Indeed, those who devour the property of orphans unjustly are only consuming into their bellies fire, and they will be burned in a blazing Fire). It is permissible for a poor guardian to consume from the orphan's money in a reasonable manner, commensurate with his care for them, which is the lesser of two things: a customary wage or the extent of his need. There is no harm in mingling with orphans in food and drink, as Allah, the Almighty, says: (And if you mix with them, they are your brothers).