Can a gay man use hand lotion as lube for sex?

Not if he is using a condom or is needing lubrication inside his or someone elses body. It will irritate the tissue and there's a bigger risk for the condom to break. For condoms there are special lubes so the rubber wont break.

Never use hand lotion or any other substance as lubrication if you are wearing a condom. Since oil and lotions are non polar, it will dissolve the non polar latex condom as well. To be safe, always use a water-based lubricant when having sex. Good brands of water-based lubricants include KY Jelly, Astroglide and Durex. Although some condoms may contain some lubrication, this is not sufficient for anal sex since the anus and rectum does not release its own natural lubrication.