I really just want some advice

I have been with my boyfriend for 2 years.

Hes my soul mate and we both know that!

He wasnt raised by his biological mother

He was raised by an aunt but he called her mom she had him since he was 6 months old

When he was 13 she passed away from cancer (11years ago)

He never dealt with the feelings that came along with that he pushed them down went to live with her son in wv and then bounced around from there

He has always had contact with his biological mom and she has come into the picture and then left numerous times.

She came back up to her home ( with her daughter grandson and husband ) about a year ago and has stayed.

We recently found out she has cancer and isnt doing well and they dont give her much longer

He doesnt show much emotions towards it

He actually told me the other day

" dont worry ill be fine remember I have practice"

I had no clue what to say

I know this will hit him hard with past feelings also

I guess my questions is how do I be there like what to say without being over pushy on the subject of him talking about it