Hi John & welcome to rootschat..
I was heading out when I originally saw your post i.e. just a quick reply!
You don't say who of his kids were married or when?
Have you checked all the marriages of his kids to find out if he was 'deceased' or, if he was alive, what his occupation was & what years?
What were the addresses given for kids marriages?
What was given as his occupation on their death certs?
Have you found a death entry for Grace (a few variants) as this will say whether she's a widow & will give an address or 'usual residence' if she died elsewhere?
Do remember that all married women in Scotland are indexed under both marital & maiden surname upon death (provided the informant knew those details).
Have you tried searching for a Will on SP?
All these things help as researchers need somewhere to begin with dates
Can you please add more info. (from the above questions) for the genealogy researchers on here.
Your new information regarding "10th Inverness Regiment of Militia" could open up a whole new world....
I would suggest you post a separate request on RC Forum (here)
http://www.rootschat.com/forum/armed-forces/but attach a link to this thread & vice versa to avoid duplication of effort.
I would advise in the "Subject" heading...
Alexander MacDonald with circa d.o.b & (10th Inverness Regiment of Militia)
The site has a lot of knowledgeable people who can guide you but meanwhile here are a few links to other threads to give you an idea of questions/replies from/to others researching same force.
http://www.rootschat.com/forum/index.php?topic=606419.0http://www.rootschat.com/forum/index.php?topic=552606.0Annie