we also use the oil filled radiators. under a hundred bucks and they heat up pretty good. 14X25 is a pretty good sized room but if the heater is next to him it should do the job. we run ours all night and it gets our bedroom pretty toasty. it's kind of hard to keep anything toasty in this weather but they do nicely.
https://www.bedbathandbeyond.com/sto...6_t-1514592103
we have one of these in each bedroom but the cheaper ones work well too.