I had a postdoc offer from a great research group at a US university towards the end of my PhD in April 2018. Around that time, a family member became severely ill. The nature of the illness was such that the doctors told me that they had to wait a few months to get a clear diagnosis and know whether it was going to be a long term condition or a one-off event. This put me in a dilemma - should I find a full time job that would let me relocate close to my family overseas if need be or should I stay in academia and hope it was just a one-off event? I decided to buy some time and wait a few months and never got back to the professor about the offer - I was very embarrassed to mention the illness as it's a highly stigmatized one. Morever, the professor wanted me to join immediately after my PhD and did not seem to be very flexible about my joining date. He never got back in touch after not hearing from me - I suppose he retracted the offer a few weeks after he made it.
I ultimately ended up delaying my PhD defense by a few months and found a corporate software job after that and started in February this year. My mental health has been slowly declining due to the fast-paced, extremely profit-driven nature of the corporate work environment and I am actually thinking of quitting and going back to a postdoc (my parents have decided to look after the sick family member so the illness is not as immediate a concern as it previously was). I apologized to the professor in March about my non-response regarding his postdoc offer and told him about the illness and that I have moved on to the industry and he was very understanding and wished me all the best.
Here is my question: I know he is still looking for postdocs. How do I even begin the conversation with him on joining his group? I am also a bit concerned that the 1 year gap on my academic CV will be looked down upon negatively in future job searches.
If it is important to this question at all, I am 27 yrs old.