Fostering friends puppy

[EastMidsMumOf1]

Due to covid and a friend of mine being a frontline worker shes asked me to look after her puppy until this is all over as she hasn't the time nor energy to look after him.
She was in the process of house training but how the hell do I carry it on? I have one other dog but he lives outdoors so never had that to deal with.
Do I take him out at regular intervals or just after food or what? Any way of limiting the amount he pees during the night? Any tips would be great please!
Hes 17 weeks if that makes any difference.

Take out very time they wake, every hour and after every meal. Let them wander in the area of where they went the last time and say a trigger word for that particular function as they are doing it, eventually they will ‘perform’ on command. Don’t scold for accidents but get pup out ASAP to finish outside. Lots of praise for doing things in the right places.

I've been taking him out in the garden and letting him wander while on a lead (dont want him having free reign as not sure how my current dog will react if he wanders into his kennel) we stay outside for around 10mins, all he will do is sniff and cry a little but as soon as I take him back in he will do his business on the kitchen floor.
If I use a puppy pad to wipe up his wee then place the pad outside would that help him realise where he needs to be doing it or does it just not work that way?
Sorry if I sound daft!

Ours was doing the same, she did eventually get it as we've been outside so much in the good weather. The wee on the puppy pad is a good idea. I did that with a dish towel and popped it by a bush. Took here there to sniff

we stay outside for around 10mins, all he will do is sniff and cry a little but as soon as I take him back in he will do his business on the kitchen floor

You really do need to stand with them until they go - be grateful it's summer and you're not toilet training in the middle of January

I stood out with mine for an hour once when he was a pup. Luckily it was July so I just sat with a book and waited - he had no choice but to go eventually 'cause I wasn't going to budge!

We took him out about every 40 minutes or so, after food, drink, naps, play and training, plus he needed out at least once a night. I had pockets full of treats and he got praise and a treat every time he went outside. We eventually added "go toilet" to it and now he'll toilet on command if necessary.

I would also get rid of the puppy pads - all they do is encourage the pup to toilet inside the house. Just clean up any accidents with a pet spray to get rid of all the enzymes.