Rashi on Genesis
וכל יש לו AND ALL THAT HE HAD — This is an elliptical phrase — the word אשר is omitted after.
Radak on Genesis
וימצא.יוסף חן...וישרת אותו, because Joseph had found so much favour in his eyes he appointed him as his exclusive personal valet. At the same time he appointed him in charge so that without Joseph’s approval nothing could be done within this household.