From: Rabbi Moshe Sofer
To: Rabbi Chaim
The Chasam Sofer rules that the husband's brother cannot reclaim the synagogue seats bequeathed by the widow in a deathbed gift, because a matnas shechiv mera has the status of a gift rather than an inheritance, precluding the recipient from benefiting from tefisah rules that apply to heirs, and the widow's long possession did not constitute chazakah since she held mezonos rights against the estate. The only limited avenue of relief is that the widow's heirs might collect without an oath an amount equivalent to two or three years of past maintenance, but this does not support a claim to all three seats.
Source: Shu"t Chasam Sofer EH II §164