Is it permissible to look at the wife of the maternal uncle or the wife of the grandfather?

It is forbidden to look at or be in seclusion with the non-mahram wife of a maternal uncle due to the legal prohibitions that result from that. However, if she is a mahram by lineage, suckling, or marriage, then it is permissible to look at her within what is allowed for a man to see of his mahrams. The wife of a grandfather is a mahram, and it is permissible to look at her within what is allowed, and believers must lower their gaze and guard their private parts.