They really don't care if the companies you worked for are still in business or not.Well, I have one more question, I would love it if you share your experience with this. Like I just recently turned 40 and I don't exactly remember where I have worked from the age of 18, I did some random job after studies and all .. but I have worked in 3 organizations in my working tenure which are no longer in business. I mean those companies are dissolved. Should I mention - Dissolved or defunct - for those companies or just let it go with my experience with them?
It happens a lot in US/Canada. Most of the companies that worked at are not there any more (acquisition by another company, purchased, combined and renamed etc)
Just list them and do not over analyzed things. If it's just a weekend of casual work, then do not need to list it or list as casual summer jobs in the following types of places (hot dog stands, street fair vandors ..etc)
Again, it's a family sponosorship. So they are not trying to see if your work experience is good enough to immigrate. They just want the true history.