Security of using DHCP and non-stanard ports for medical devices

I recently came across this comment written in a journal article.

“Lastly, medical apparatus are expected to use Dynamic Host Configuration Protocol (DHCP) for the allocation of their IP addresses and even worst [sic] use non-standard ports for their communication creating an unstable environment of information that is hard to address”

Can some explain why DHCP and non-standard ports are considered so risky?