What is the ruling on the wife's mother kissing her daughter's husband, hugging him, and sleeping with him in the same bed, on the basis that he is like her son?

The wife's mother is forbidden to her daughter's husband. However, it is impermissible for her to sleep with him in the same bed, or to kiss him with desire, or to embrace him, because this could cause temptation. This is unless she is an old woman for whom there is no desire, in which case there is no harm in her kissing him out of mercy and compassion, but without sleeping with him.