Not an expert, but i do grow a few Acers. they need: semi-shade, not exposed to cold winds, and a slightly acid, woodsy soil [ leaf mould, ericaceous compost and some John innes No. 3 ]. Dont let them dry out, but dont drown them. Given that lot, they should thrive and act as a constant reminder of your dad.
Agree with that - moist well draining soil is key.