I posted this a few months ago when someone else had the same issue:
How is he getting home? If his suitcase is going into the car, you should put it inside a bin bag (or two) to prevent the car becoming infested.
Firstly, he should make sure he's not bringing any back on himself. If possible, he should check the clothes he wants to wear home. Last thing before leaving the hotel should be shower and get changed, without sitting down again or putting clothes on the bed etc. He should also shake himself off when leaving and check the bottoms of his shoes. When he gers home, he should strip off his clothes into a bin bag. This should ideally be done outdoors but I can understand your neighbours might not enjoy the show!
Shoes should be left outside until they can be checked. Bedbugs don't generally like to stay on people but it's worth having another shower when he gets into the house anyway.
Suitcases/bags should be left outside and then all clothes emptied into bin bags. When the suitcase is empty, check the whole thing, especially in cracks and crevices such as around the zips as this is where bedbugs will hide. Eggs look like a grain of rice but smaller. Or just chuck the suitcase away since it's old!
Next, the clothes - Do you have a tumble dryer? If so, put everything dry in there for 30 minutes - this is long and hot enough to kill all in the cycle (nymphs, adults and eggs). Don't overload the machine so everything gets sufficiently hot. When heating everything dry there is less damage and shrinkage to your clothes. I did this with all my clothes and had no damage at all.
If you don't have a dryer, put everything into the washing machine on a hot wash. Do this from the bin bags to prevent any bedbugs from escaping into your house. Bin bags should be thrown away into the outdoor black bin after use. Anything that can't be washed on a high heat or go in the dryer should go into a ziplock bag and then into the freezer for at least 4 days. Put the rucksack into a bin bag and into the freezer if it will fit.
To be extra sure, you could buy Cimexa from Amazon, which dries out and kills bedbugs on contact. It's a form of silica so non toxic but should be applied with a dust mask. You could apply this in the suitcase if you don't want to get rid, and also put a bit in crevices on your bed.
I encountered bedbugs in an Airbnb last year and went a bit crazy trying to make sure I didnt bring them home. I even enquired about a bedbug sniffer dog coming to my house! If you have any questions, feel free to message me.