What is the ruling on contacting the mother of a detained colleague to reassure and comfort her, and the ruling on visiting her? And what is the ruling on asking a non-mahram woman about her well-being and congratulating her on her wedding, especially if she is a relative, assuming there is no fear of temptation?

If there is assurance that no fitna (temptation/strife) will arise, it is permissible to speak with a colleague's mother to inquire about her, offer condolences, and ask about her son's condition. It is also permissible to inquire about a female relative (who is not a mahram) and congratulate her on her wedding. Ascertaining the absence of fitna requires honesty with oneself, an awareness of the danger of fitna involving women, and fear of Allah.