Tracing relative in Australia (possibly still alive)

[YesMudder]

I'm trying to track down my Grandad's brother, Frank Thomas who was born in Sculcoates, Hull, Yorkshire in 1925. He went to Australia during/shortly after World War Two, but they kept in touch for many years.
My grandad is in his 80s and is a little confused now - he can't remember Frank's contact details or if he has passed away. He would very much like to get in touch, or with Frank's wife Agnes or son Ronald. My nana is unfortunately very ill and he would like to speak to his brother and to let them know about her illness.

Any advice on where to start would be much appreciated. I have some family history research knowledge, but I know nothing about tracing living people, especially not in Australia. I looked at the Salvation Army, but I can't afford it at the moment. Can anyone advise where to begin?

Many Thanks for any advice

Do you know anything about where he went to or the last place he lived- not an address just a place?

If you do, find the name of the local newspaper on the internet and write a letter and email it to the editor asking if they will print it. Give as many details as you know and explain why you want to get in touch. I found my dad's brothers children like this who the family lost touch with in the 1960s. Someone who still knew them got in touch with them and told them and they got in touch with me. It took less than a week start to finish. We are still in touch 7 years later.

Have you looked on Facebook for Ronald? Do you know his approx location and dob?