What would be considered the reasonable compensation for a trustee if he is also a beneficiary?

What is reasonable depends on several factors including whether the trustee is a corporate trustee, a professional trustee, a family member, etc. it also depends on the complexity of the work performed by the trustee, the qualifications of the trustee, and the assets held by the trust. Corporate trustees often charge a percentage fee on an annual basis, and a family trustee may take payment on a more informal basis. Compensation may also be dictated by the terms of the trust, and could be subject to the approval of the Court in some cases. With so many variables, you would be best served by seeking legal counsel in your area to assess your particular situation. Good luck.