PIP/ESA temporary change of circumstances?

Hello. I get PIP (enhanced mobility and enhanced daily living) and ESA (support group) with severe disability and disability income guarantee.

I live alone and my only son lives several hundred miles away and is buying a house with his fiancee. For work reasons there is a query about whether he might move in with me 4/5 days a week, this arrangement, is it were to happen, would last for maybe 6-18 months.

Would I have to claim UC, or be protected as I am, or does anybody know what would happen. I want to be helpful to this young couple but worry whether the whole thing is too much for me and I ought to say no. Does anybody know what would be involved?

Thank you for your reply. If my son does come to stay would I simply report the change to ESA (DWP?), lose the live-alone part until the arrangement comes to an end and then inform them again. I am very relieved to think things might be so simple as I had imagined I would have to start over again with UC. Thanks again

Thank you again for your reply. If my son were to find the drive back to stay with his fiancee in their house was too much and stayed with me 7 days a week would this make any difference? Is it the part time part that makes it unlikely I would need to transfer to Universal Credit? It is unlikely the arrangement would be come permanent, although it might continue for as much as 18 months.

I hope you see this further question ... not sure if I'm doing it right. Thanks.