Ex Problems!

K well i was dating my ex for about a year, we broke up about 4 months ago & now iv been dating a new for about a month. Me & my ex are still friends, we care about each other.. things just didnt work out. Recently i found out his family isnt doing good & his dad might have cancer. I want to message him & have a convo & ask about how he & how things are doing. I dont miss him & would never get back with him but id still feel guilty if i had a convo with him about that stuff bc im in another relationship now?  What should i do?