Hello and welcome
Nice watch, and a nice thing to inherit.
From the case it is probably 1950s, the first half of them.
The 105 is Lemania's base level chronograph range, but it is still a nice thing, and Lemania made them well anyway.
Is there anything engraved on the back?
We could tell further from the movement, but I do not recommend you take that apart unless you know what you are about.
Our host, Al, can arrange for a service for you, I think, and I can recommend others if he thinks not.
A new crystal is very easy to find, luckily it looks like the dial and hands are fine.
And for the cost of a service and new crystal (think around couple of hundred pounds plus parts) you'll have a lovely watch worth three or four times that amount.
Movement parts can be found, but are relatively pricey, so if something is more comprehensively broken (or water has got in and corroded parts) then the cost could escalate quite a lot.
These watches hate water, and the age of this watch shows pretty basic rectangular pushers and a simple crown, so there is very little inherent waterproofing on this watch.
Let us know how you get on, and post some more photos if you feel like it.
BTW, where are you based?
If it's Lemania-powered, I'm interested. Tool Chrono - interested. Dive Chrono - interested. Interesting - interested