Is my dad seeing a prostitute (or many)?

Since there is little evidence to support this I would assume no.There are so many other things he could be doing.

in the adventure that your dad's call isn't John, then.....sure....he's seeing a prostitute. yet, being that your dad is a unmarried divorcee with a new child, that's very an excellent thank you to "get some" without strings linked. this way he would not have all the issues of a dating and might commit maximum of his time to you. Yay! bypass Dad!

maybe your dad went to his girlfriends house to have sex seeing that the daughter was by his house. so they knew they can get down on it in peace.

dont assume stuff please. if you tell people that he is seeing a prostitute when in fact he wasnt then you have damaged your father's reputation and yours. come to think of it, if your father is seeing a prostitute you will be known as the son of a father who is seeing a prostitute, and it will be assumed that you will turn out that way yourself.

if you have issues with your father dont make rash decisions that will backfire in your face.

no, and even if he was, should it matter? My dad had unprotected sex with a prostitute, and guess what, he died of HIV, so be grateful you even have a dad, instead of worrying what he is up to, how would you feel if your dad died and you could never see him again? Please value the time you have together, don't waste it in suspicion and other trivial bs.

you have no real reason to believe anything bad, even IF he chooses not to tell you. You are getting way too carried away by your imagination! Chill out, and worry about YOU.

Is it close to someones birthday? Maybe he went out to get something for a surprise.

And maybe it is he is getting ready to marry his girlfriend.