So long as children are either the product of two trial members or one parent is at least 1/16th M-Pequot, they are tribal members. I knew a fellow whose wife was 1/4 M-Pequot. His wife and his kids were tribal members but he was not. It’s all a silly ruse since the original Pequot tribe, by their own history, disappeared about 1740 when they battled (and lost) with the Mohicans. The survivors were assimilated by other tribes.
This happened big time in 1648 when a very bad winter beat up everybody ~ the Iroquois were reported to have forced a tribute of about 15,000 men suitable for service as warriors.
The Pequot were certainly an organized warrior elite of some consequence up until 1648. Afterward they were still a warrior elite but they were no longer of consequence.
That period of time also saw the Iroquois defeat the Mohicans, who were then adopted by the Oneida ~ right into the ranks of warriors. War was, as it happened in those days, a private matter, but business was business. So, if the Pequot were adopted by the Mohicans, that had to be earlier than 1740 because the Mohicans had been adopted themselves by the Oneida.
Or, your reference is to the Mahicans, a totally different coastal group probably speaking the same language as the Pequot. I'd suspect they got absorbed by one of their tributary tribes, but someone with more information on NE tribes might well know exactly what happened.
They are back, this time equipped with a casino ~ giving them a long life!
The Oneida at Lake Winnebago also have a casino. The Muncee Band, the greater part of the tribe in that area, ARE the remnant of the Mohicans and the Brothertons ~ to the extent the Brothertons didn't wander off with the Kickapoo.
I follow these handful of tribes very carefully when they get an historic reference so I can see if I can spot one of my ancestors marrying in for a year or two (one of them did a couple of dozen brides over the years, at least 3 of whom were Indians now in tribes located up at Sault St Marie.