Can one's Naam Kamaaee or Seva benefit dead ancestors?

Someone asked me the question whether one's spiritual efforts (e.g. Naam Kamaaee, Gurbani Paath, or Seva) can benefit one's dead family members or ancestors/lineage (past and or future), and an explanation of how it works out.

Daas had the idea that pangtee'aa like the following are referring to redeeming the future "kul" (lineage).

ਆਪਿ ਤਰੈ ਕੁਲ ਸਗਲੇ ਤਾਰੇ ਗੁਰਮੁਖਿ ਜਨਮੁ ਸਵਾਰਣਿਆ ||੩||

My limited understanding led me to believe that someone like Bhai Sahib Bhai Randhir Singh Ji not only saved himself but all those who were part of his "spiritual" family, and those who did Sangat with him (in person or with his books) and got inspired to japp Naam as well were saved. This would still then support the idea of:

ਕਰਮੀ ਆਪੋ ਆਪਣੀ ਕੇ ਨੇੜੈ ਕੇ ਦੂਰਿ ||


Can Gursikhs please share their thoughts.

Bhai Sahib Bhai Randhir Singh Ji has mentioned through Gurmat Naam Abhyiaas ones ancestors get redeemed ( Gurmat Naam Abhyiaas Kamaee).

ਜਿਸੁ ਸਿਮਰਤ ਸਭਿ ਕਿਲਵਿਖ ਨਾਸਹਿ ਪਿਤਰੀ ਹੋਇ ਉਧਾਰੋ ॥

Pitree here means ancestors. So its clear through Gurmat Naam Abhyiaas not only do we get mukhti our ancestors get redeemed from some joon or world.

It seems Guru Ji has answered this for you directly. Today's hukamnama from Harmandir Sahib is:

Wandering and roaming around, I met the Holy Perfect Guru, who has taught me. All other devices did not work, so I meditate on the Name of the Lord, Har, Har. || 1 || For this reason, I sought the Protection and Support of my Lord, the Cherisher of the Universe. I sought the Sanctuary of the Perfect Transcendent Lord, and all my entanglements were dissolved. || Pause || Paradise, the earth, the nether regions of the underworld, and the globe of the world — all are engrossed in Maya. To save your soul, and liberate all your ancestors, meditate on the Name of the Lord, Har, Har. || 2 || O Nanak, singing the Naam, the Name of the Immaculate Lord, all treasures are obtained. Only that rare person, whom the Lord and Master blesses with His Grace, comes to know this. || 3 || 3 || 21 ||

Waheguru. Hukunama has given a very clear answer: To save your soul, and liberate all your ancestors, meditate on the Name of the Lord, Har, Har

What about the ancestors who have taken rebirth?