Question

but then I wondered if it was something to do with my mother, who I knew wasn't very well.

یه کم لغوی تر جمله رو معنی میکنید

Answer 1

ربط داشتن به, مربوط بودن به, دست داشتن در

have/be to do with sb/sth

to be about something, be related to something, or be involved with something 

>>>

+ Their conversation had been largely to do with work. 

+ I’m sorry about the accident, but it’s nothing to do with me ( = I am not involved in any way). 

+ This question doesn’t have anything to do with the main topic of the survey.

 

Longman Dictionary

https://www.ldoceonline.com/dictionary/do-with