How quickly can you get divorced and remarried?

[Yellowbowlbanana]

My mum's partner has been diagnosed with terminal cancer. He is very poorly. They have been together 25 years. He said yesterday that he'd like them to get married. Slight issue is that he is already married. He split up from his wife 40 years ago but they never divorced. Is this something we can fix in time? I actually don't think he has very long left, maybe a few months.

I would think that being separated that long would mean that the divorce papers only need signing & then putting through court, speak to a solicitor, they should be able to give a time for how fast it can be done.