A booklet of "go and get some sleep idiot!" vouchers, for when he's about 4 - 6 weeks in and has been doing all he can to help mum manage and forgets about himself, best to have a list of people happy to receive these as well.....probably all your mates and your mum (you may not want his mum helping...just saying....).
Think about those things he's said he used to do with his Dad as one or two might be something he'd like to do with his child/toddler/teenager....do a bit of digging and organise some tickets or suggest.....I took my little boy to my local posh pub for a Diet Coke in the afternoon a couple of times whilst he was in his BabyBjorn as it was half way home and just before the big hill (live in Bath) sounds odd but it took five minutes and was more than my Dad had done at all.
Or if he likes movies arrange a membership to Lovefilm or the like for when he has half an hour and can just switch his mind off with some mindless Hangover type movie, or get in a load of his type of DVD's.
If this is crap to you tell me to sod off.