Can a foreign resident be a trustee of trust?

Any natural person can be a trustee of a trust.  Note that in Victoria, if the trustee remains out of Victoria for more than one year (which will be the case for a non-resident), the appointor may appoint one or more other persons to be trustee or trustees in place of the existing trustee.  Therefore, it would be prudent for your client to also be the appointor of the trust to protect his interests and not be replaced as trustee.