I think CFK's advice is good. If he does seem above grade level, then a good period of unschooling may be called for. And you've got all the time in the world right now.
I'm not a homeschooler, but I've thought about it. I could see that I would feel like I need to have some productive plan for each week and that it would be helpful at times to rely on a formal curriculum. But, the great thing about homeschooling is that you can do it any way that you and your child want. This might be a sign that your DS needs to homeschool in a more casual way right now. And really, he is only a 7 year old little guy, and to top it off one who has been through a lot this year. Maybe you can wait until next year to teach him reasonable work habits!
If you are wanting to encourage academic activities, what about playing off of your son's fantasy world? Can he dictate his stories to you? You could ask him questions about his stories and perhaps do some research to get more information on his topics of interest. You could encourage him to make lists -- of characters, of locations, etc. You could encourage him to draw maps of his inner worlds (I'm not sure if his difficulty with writing is motor-related or desire-related) and label them. You could encourage him to type up his stories or even e-mail you his latest story developments. On the e-mail note, you could just have him e-mail relatives to practice composing and typing.
As far as math goes, you could just try to work math into your everyday conversations. You could cook a lot. Give him a small allowance and have him keep track in his journal of his income and expenditures. Give him a watch and have him figure out things like elapsed time. You could have him figure out the ratios or fractions of good guys to bad guys in his fantasy world. At least around here (Everyday Math), the formal curriculum is about math skills you encounter in everyday life, so you should be able to "sneak" these skills in without him having to do formal math.
Most importantly, don't be too hard on yourself! Any time you're spending with him is educational in some way.
