Yes, you are eligible for the Family Reunification Process. The Law specifies that family reunification may be granted to ascendants in the direct line and first degree of the resident or their spouse or common-law partner. In other words, this provision allows for family reunification of parents or parents-in-law (first-degree ascendants), which is your case, of the resident in Portugal or of their spouse or common-law partner. However, keep in mind that although the residence permit can be granted, there’s also a necessity to show that you still are dependent on your son/daughter-in-law. I also noticed that you mention permanent residency in your question. Please note that, in order to get permanent residency, you and your daughter/son-in-law need to legally stay in Portugal for a period of at least 5 years. Only after this period you can then request the permanent residency.
