If an abhyasi who has practised well is no longer attending satsanghs or individual sittings, is it ok to give absentia sittings to that abhyasi without informing him? Will it bring him back?

If a practising abhyasi drops off, you can give absentia sittings without his knowledge. Will it bring him back? That is in Master’s hands, and in the abhyasi's hands. We do our best to serve Master sincerely. You may also want to contact this abhyasi, to ask how he is doing, visit him or invite him for tea, without any pressure to have a sitting. Often, when abhyasis drop off, it is because of the difficulty they experience with the movements associated with their spiritual yatra. Some reassurance and support from a preceptor, and understanding of the challenges along the path, can help a lot in bringing them back.