Canada is a solid choice, but encourages bad gameplay that he won't learn from if he wants to improve in general for Deity (as in, you can get away with a lot of stuff that none of the other civs can, and any game plan he learns from that is not directly translatable to different civs he tries later on).
I'd personally pursue two opening styles and choose "easy" civs for that purpose:
One is the aggressive opener (where you stop at 2-3 cities and conquer your neighbour with units produced off those) - good choices for these are Sumeria, Gran Colombia, Nubia, Gaul, and maybe Aztecs.
After you conquer your nearest neighbour, you start developing your new empire (which should consist of at least 6 cities total by then).
The advantage of this opener is that you are generally safe from any immediate neighbours and have an army to discourage another declaration of war. On the flip side, you are most likely underdeveloped (though you might have taken a few campuses off your neighbour if lucky) so you need to work on that immediately once you secured victory.
Speed is of the essence here though, as well as a good tactical sense so that you are able to conquer their army before they tech up too far, cities before they get walls, as well as hold onto those cities.
The other style is the peaceful opener, where you early on identify where your neighbours are, where you have room to settle, and go from there - good choices here are civs like Korea (possibly Maya, but their early build order is very different from other civs and not recommended if you aren't 100% sure of what you're doing), Australia, Gaul among others.
These civs have an advantage in very early and strong science (which lets you unlock new tech like Horsemen and Crossbowmen sooner), or very early production and culture (which lets you unlock the settler card and Oligarchy sooner, and generally produce units/infrastructure on a whim).
Forward settle maybe one or two cities somewhat near the neighbour (but not so that you lose loyalty now or in the future, and not so close that they take it as a sign of aggression) so that you stake out that land as your future border.
Then continue settling your hinterlands.
You don't need as much army for that, and depending on if you have room to settle just a few cities (up to 8) or a large number of cities (10+) you decide on whether you need the Ancestral Hall or not (you obviously need the settler production card, and if possible use a monumentality golden age to buy settlers en masse).
From those freshly settled cities, work on infrastructure to the extent that you feel safe (be mindful of army value scores as usual, you usually don't want to be below 1/3 to 1/4 of the neighbours value) - plopping down campuses, comm hubs, worker improvements etc.
The advantages of this build are that you get right on to improving your empire from the start, getting high adjacency (if possible) campuses down to lock in their cheap costs, as well as settling and improving features.
The drawback is of course that your neighbour is more free to do as he pleases, so you need to watch out for when you need to start unit production.
Mind that if you do have a neighbour and you don't plan on conquering, always use the scout/warrior to scout for any incoming armies - this is vital.
I know most people want to use that scout/warrior to run around, get tribal villages, clear barb camps and meet city states, but if your spidey sense tickles regarding your neighbour, keep at least one of them near to spot what your neighbour is up to - you'll have a much higher success rate since your issue is early aggression from the AI.
If you do spot them ahead of time, you should swap production over to warriors/archers and fortify your nearest border city ASAP.
Having a few warriors fortified on hills/woods etc. outside a city will make them very tanky while your archers behind them whittle down their main force.
Needless to say though, Deity early game is hard, and you can't use a strict cookie cutter build in all situations.
Therefore you always need to pay attention to your surroundings (are there units incoming? How close are their cities? Are there any natural chokepoints between my city and their army, that I can hold and fortify at to stop their attack?) and your neighbour's score (especially army value and science per turn, those are good predictors of whether you might run into trouble in the short and medium term).
