Sorry for your loss. Losing a child must be the most emotionally difficult feeling to bear.
I grew a rose for someone....the name and colour were perfect. It flowers at the,right time. I grow a dicentra spectabile for my young nephew ...it flowers wonderfully at the right time too, viz., spring.
November is difficult. A camellia is nice. Full of promising buds in November to,produce its flowers in spring.
Lomicera winter beauty is a shrubby honeysuckle with scented late winter flowers and, again, has buds in November.
Choisya sundance is a lovely,yellow evergreen shrub that looks good in November and produces scenfed flowers in spring
Daphne Odora aureomarginataIas a lovely evergreen shrub that looks good all year round and has late winter beautifully scented flowers
What sort of shrub would YOU ideally like to remember your son by? Evergreen? Scent? Winter flowering heathers are full of buds and flowers over autumn and winter. Maybe a little plaque too with his name on it?