Well there's your 'way in' so to speak. Ask them if they have any photos of David and the family in general, and explain that you have been considering making a family tree as a tribute for the family. It's slightly economical with the truth, but the circumstances warrant it in my opinion. I think this way you will avoid upsetting anyone, and it's a perfectly reasonable request
My hubby (also David) died more than 10 years ago now, from a massive heart attack, and his mum was also still living - aged 95 years! He was her only child, although he did have a brother who died in infancy, and also her last remaining blood relative, so it was no real surprise when she died quietly just 3 months later. The amazing thing is she had managed to reach that great age without suffering any major illness throughout her life, and we felt sure that if David hadn't died so suddenly she would still be with us now. She pretty much gave up on life really, which was understandable. As she said, you don't expect to be going to your child's funeral when you are 95 yourself
Anyway, best of luck and do let us know how you get on
