Legal Question in Wills and Trusts in Canada

Yes he can. As part of the probate application process, your executor will be required to send your son a notice advising that your executor is applying for probate with a copy of the will. Your son may make a claim, but whether or not he will be successful is a complex question that is beyond the scope of LawGuru. In British Columbia, it is generally adviseable to include in your will the reasons for why you are not giving anything to your son - this may or may not be required in other Provinces, but in BC it is. Your son is most likely not able to claim against your second wife's estate, but this would depend on a number of factors one of which is whether or not he was adopted by her or if she helped to raise him), which again are beyond the scope of LawGuru. Please consult a lawyer who is experienced in wills & estates.