Below are some links for brain injury support groups.  There will likely be other groups in these countries, and other countries will also have such groups: 

• Australia - https://www.braininjuryaustralia.org.au/services/

• United Kingdom - https://www.headway.org.uk/
• New Zealand - https://www.brain-injury.nz/
• Canada - https://www.braininjurycanada.ca/
• United States - https://www.biausa.org/brain-injury
• Ireland - https://headway.ie/