A solicitor may not have been involved - there's no legal requirement for them, and many people do it themselves (i.e. spouse, sibling or elder child etc).
If there was a will, it should have been dealt with via probate and you can obtain a copy of the will and probate to see exactly what it said.
However, they may not have been a will, in which case someone would have to apply for letters of administration.
If all assets (property, bank accounts etc) were in joint names, then they pass to the surviving spouse automatically, so what the will says is irrelevant as that only applies to assets that weren't jointly owned.
If there's nothing registered at the probate office, i.e. no will, then either he didn't make one or it's been lost/ignored/destroyed.
I don't suppose you know which solicitor he'd have used? If so, or if you have any realistic guesses, then you could always contact them to ask if he had made a will with them.