Not ideal with the time you are spending at work but doable.
Visiting your mum for a couple of days may be an issue. Is "couple of days" just one night? Or two nights and three days? I wouldn't recommend leaving cat on his own for more than one night/two days unless you have someone to pop in on regular basis.
You could consider a cat flap so your cat could go outside when you are not in. Just perhaps not straight away, give him a couple of weeks first.