A couple whose son needs 24-hour care say they have been left confused as to whether they are on supermarkets' list of the vulnerable because of delays getting a shielding letter.
Matthew and Lisa Williams, of Swansea, are full-time carers for Macsen, eight, who has a rare genetic disorder and suffers multiple daily seizures.
They say they have been unable to secure supermarket delivery slots during the coronavirus pandemic because they did not initially receive one of the the 80,000 letters sent to the vulnerable with advice to stay indoors for 12-16 weeks.
The Welsh Government said people should contact their GP if they believe they should have a letter.
After the Williams family did not receive "shielding letter", the hospice that supports them intervened and the letter was then sent out by their GP.
But the Williams family say they are still unable to access the priority delivery slots for the vulnerable, and are frustrated that a lack of transparency in the system means they cannot check if they are now on the list.
Macsen has a condition called Grin 2-A, which causes epilepsy and symptoms similar to cerebral palsy.
The family initially contacted their regular supermarket and registered as vulnerable, but they say since the list of vulnerable people was provided to supermarkets by the Welsh Government, they have been unable to access those slots.
Mr and Mrs Williams said they found it increasingly difficult to get food delivery slots since the letters went out and recently spent two days trying to organise a delivery from their usual supermarket.
"It's frustrating, we've got enough to deal with trying to keep our son alive without constantly having to go online to look for food delivery slots," said Mrs Williams, who gave up her job in the health service to care for Macsen.
"Not being able to access food shopping, which is vital for us, is really, really stressful."
Macsen receives palliative care from Ty Hafan children's hospital.
Both his parents also live with underlying health conditions.
Mr Williams has a degenerative illness which causes muscle wastage, impairing his mobility, while Mrs Williams suffers from severe migraines, endometriosis and fibromyalgia.
The couple also have a 12-year-old son, Ioan.
They have all been in self-isolation for six weeks, after Macsen had to be treated in hospital for a cold triggered by another strain of coronavirus.
"He ended up on a high-dependency ward and that's after what we refer to as a common cold," said Mr Williams.
"If he caught this [Covid-19] he would be in very great danger, so we have to keep him protected."
The family's GP and Macsen's consultant at Ty Hafan have told the family they meet the criteria for shielding themselves for 12 weeks during the crisis.
But they have not received any offers of help or support from the local authority or elsewhere and, without the shielding letter, are unsure how to go about requesting this.
"We've always had food and pharmacy deliveries but now everyone is sharing those and there's nowhere near enough to go around," said Mr Williams.
"There's no transparency in this process, no way for us to contact anyone and say 'am I on the list?'"
Mrs Williams added: "We're already aware of how fragile Macsen is.
"We're thankful that we've had him with us for eight years and we spend every day just trying to make sure he's here for another eight years.
"He's under palliative care and we don't know how long we have got with him, so we do everything we can do to keep him safe."
A Welsh Government spokesman said: "People who feel they are in the most-vulnerable categories and who have not received a letter can contact their GP to discuss the matter.
"If their GP is in agreement, then they are able to issue a letter.
"So far nearly 2,000 people have been added to the central list by their GPs."