Death certificates for someone who died this year are not on-line. You would need to contact GRONI in Belfast and get a copy of the certificate from them. It should contain Alex’s date of birth, from which you can get his birth certificate and work backwards. Contact details for ringing or e-mailing GRONI:
https://www.nidirect.gov.uk/contacts/contacts-az/general-register-office-northern-ireland
Deaths over 100 years, marriages over 75 and births over 100 years are on-line, so once you get back before those cut off points it is easier to compile information.
In the 1911 census of Kilkeel there were 43 people named Newell. I noticed this family who were fishermen. You may find they are related:
http://www.census.nationalarchives.ie/pages/1911/Down/Kilkeel/Harbour_Road/245457/
Newell Thomas John of Harbour Road Kilkeel county Down fisherman died 31 December 1948 Probate Belfast 31 October to Thomas Graham boot and shoe merchant and Thomas Trimble publican. Effects £7211.
The Northern Whig for 3rd Jan 1949 carries a short obituary mentioning that Thomas Newell had been a pioneer of the dual purpose fishing boat, and had also latterly been a fish inspector at Kilkeel.
Given how recently Alex died you might find getting information and photos is something that next of kin or surviving family might be able to help with.
