Hi, first of all sorry for your loss, even if you weren't close it must have been a shock.
First of all is there a will, if there is then you need to find out who the solicitor is taking care of his affairs, then find out if your in the will, you maybe in it. If not you can try to contest it, but very few people are successful in doing this, and it costs a good few thousand pounds,
If there is no will, was he married? Or was he living with someone for more than 3 years, if not then you most likely will get something if not most of it.