Honestly my time spent on it depends on how hard i'm trying to gain at the time, if i'm not i spend very little time thinking on it. if i am gaining i think about it pretty regularly as i consider snacks and meals.

I found some old clothes today that i used to wear when I was in school, most of them were woefully too small to even get over my thighs, then I found a few pairs of jeans from College. Mostly size 48-50 waist jeans so I decided to try them on. I added pics or the tightest and loosest to my profile if you want to see.
I'm still impressed that size 50 just barely fit under my belly, the one pair that fit over any of my belly was a super relaxed fit.

I also found a pack of XL undershirts in the box, so i busted one out for the photos. it barely reaches my navel. I'm also pretty sure the last time i wore an XL was maybe 6th grade... no idea why I had a pack of shirts this small.

Da Vinci's Notebook - Another Irish Drinking song.

One of my favorite things coming out of these studies is the fact that most people have an outdated mental image in their head and see themselves as smaller than they currently are. So if you have 2 large people they can both be the others fat friend.

In about the same time period I've gone from about 20 stone to about 28 stone

I've seen several of my thin friends end up heavier due to hanging out with heavier ladies at work so i'd say the idea is well founded.

Most the reputable articles I've seen claimed that since it is a matter of lifestyle the people around you the most are influenced the strongest. So if you tend to eat large portions people around you are more likely to eat more because it doesn't seem as bad. If they put on a few pounds and they have a fat friend to compare themselves to they are more likely to play it down. It really boils down to a case of "I might be bad but at least i'm not..."
Therefore, revel in your fat and gaining lifestyle and it'll make people around you fatter.

I wouldn't say dangerous, but its probably not something you want to do long term. A tablespoon of either liquid gives you 16% of your recommended saturated fat for the day, if you're using say a cup each you're looking at 500% of your recommended saturated fat before adding the nutella. So in the long run its bad for your heart, but then so is gaining.

I'd consider finding a different liquid to cut it with instead of cream if you want to use it long term. The cream and the Coconut milk are pretty comparable nutritionally so increasing one and eliminating the other won't do much aside from change the consistency.
Normally I'd make a suggestion here but I'm not familiar with coconut milk in my cooking so I'd want to experiment with it before suggesting changes.

Well if you're planning to start gaining I'd say money is always helpful. Food expenses increase the bigger you get. Luckily you can get fairly large clothes cheaply as long as you're not looking for dress clothes.
Obviously a sedentary job is preferable if you're starting to gain, but not necessary.
I'd argue that one of the best things you can do to set up for gaining is lay out your living space to minimize movement and maximize your chances to graze on snacks.

As to it being easy or hard that depends on you and your metabolism.

Generally just briefs, during winter maybe socks too. I'll wear sweatpants occasionally but they are generally too warm for me.

Well purely from a math stand point he'll need like 2000 extra calories a day to pull it off, so maybe go check out some of the gain shake recipes on here is probably a good start.

As always, i'm going to recommend a bit of moderation in junk food. Burgers may be cheap and calorie dense but all that grease is going to wreck your stomach and isn't good for you in the long run. Honestly, huge portions of what he eats now is probably the best advice.